Added Capsule z-stream upgrade support

[sthirugn]

Closed #3

[sthirugn]

Test notes:
6.2 to 6.3 upgrade:

# ansible-playbook capsule-upgrade-playbook.yml 
PLAY [capsules] ******************************************************************************************************************************************************
....
....
PLAY RECAP ***********************************************************************************************************************************************************
capsule.example.com : ok=16   changed=13   unreachable=0    failed=0   

Friday 04 May 2018  15:40:43 -0400 (0:00:00.822)       0:03:01.717 ************ 
=============================================================================== 
capsule_upgrade : Run capsule-installer command -------------------------------------------------------------------------------------------------------------- 91.55s
capsule_upgrade : Update yum --------------------------------------------------------------------------------------------------------------------------------- 30.86s
create_certs : Create capsule certs on satellite for capsule upgrade version 6.3 ----------------------------------------------------------------------------- 26.17s
capsule_upgrade : Stop katello-service ----------------------------------------------------------------------------------------------------------------------- 10.76s
repo_enable : Enable required repos for capsule installation/upgrade ------------------------------------------------------------------------------------------ 4.44s
repo_enable : Clean yum --------------------------------------------------------------------------------------------------------------------------------------- 3.90s
repo_enable : Disable all repos ------------------------------------------------------------------------------------------------------------------------------- 3.60s
bootstrap : subscription-manager refresh to get new repos for Capsule upgrade --------------------------------------------------------------------------------- 3.49s
Gathering Facts ----------------------------------------------------------------------------------------------------------------------------------------------- 3.10s
create_certs : Copy the required certs to the capsule --------------------------------------------------------------------------------------------------------- 1.10s
capsule_check : Check capsule status -------------------------------------------------------------------------------------------------------------------------- 0.82s
repo_enable : Remove epel ------------------------------------------------------------------------------------------------------------------------------------- 0.54s
create_certs : Create /certs directory on capsule ------------------------------------------------------------------------------------------------------------- 0.40s
create_certs : Create /certs directory on satellite ----------------------------------------------------------------------------------------------------------- 0.39s
bootstrap : Detect the hostname of Satellite ------------------------------------------------------------------------------------------------------------------ 0.24s
create_certs : Create capsule certs on satellite for capsule install version 6.3 ------------------------------------------------------------------------------ 0.07s
bootstrap : set_fact ------------------------------------------------------------------------------------------------------------------------------------------ 0.05s
capsule_upgrade : Run capsule-installer command --------------------------------------------------------------------------------------------------------------- 0.04s
create_certs : Create capsule certs on satellite for capsule install version 6.2 ------------------------------------------------------------------------------ 0.04s
create_certs : Extract the capsule-installer command for capsule install -------------------------------------------------------------------------------------- 0.03s

6.3 to 6.3 z-stream upgrade:

# ansible-playbook capsule-zupgrade-playbook.yml 

PLAY [capsules] ************************************************************************************************************************
...
...

PLAY RECAP ************************************************************************************************************************
capsule.example.com : ok=5    changed=4    unreachable=0    failed=0   

Friday 04 May 2018  15:43:09 -0400 (0:00:00.925)       0:01:36.922 ************ 
=============================================================================== 
capsule_upgrade : Run capsule-installer command -------------------------------------------------------------------------------------------------------------- 78.53s
capsule_upgrade : Stop katello-service ----------------------------------------------------------------------------------------------------------------------- 11.01s
Gathering Facts ----------------------------------------------------------------------------------------------------------------------------------------------- 3.43s
capsule_upgrade : Update yum ---------------------------------------------------------------------------------------------------------------------------------- 2.94s
capsule_check : Check capsule status -------------------------------------------------------------------------------------------------------------------------- 0.93s
capsule_upgrade : Run capsule-installer command --------------------------------------------------------------------------------------------------------------- 0.03s

[sthirugn]

Tests passed, merging.