scylla_install_image:remove /var/cache/debconf/config.dat after image creation

[yaronkaikov]

during our rolling-upgrade process, we keep getting the following failure:

Command: 'sudo DEBIAN_FRONTEND=noninteractive apt-get -o Dpkg::Options::="--force-confold" -o Dpkg::Options::="--force-confdef" upgrade -y '
Exit code: 100
Stdout:
linux-aws linux-headers-aws linux-image-aws
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up shim-signed (1.40.9+15.7-0ubuntu1) ...
mount: /var/lib/grub/esp: special device /dev/disk/by-id/nvme-Amazon_Elastic_Block_Store_vol0b2a94761ddb1d0c5-part15 does not exist.
dpkg: error processing package shim-signed (--configure):
installed shim-signed package post-installation script subprocess returned error exit status 32
Errors were encountered while processing:
shim-signed
Stderr:
E: Sub-process /usr/bin/dpkg returned an error code (1)

Happened for all images

As suggested by @syuu1228, let's remove config.dat once we complete the image creation

Closes: https://github.com/scylladb/scylla-enterprise/issues/2818

[yaronkaikov]

Verified with https://jenkins.scylladb.com/job/scylla-master/job/releng-testing/job/next-machine-image/149/

scyllaadm@ip-10-0-1-231:~$ ls -la /var/cache/debconf/config.dat
-rw-r--r-- 1 root root 0 Jul 16 10:56 /var/cache/debconf/config.dat
scyllaadm@ip-10-0-1-231:~$ cat /var/cache/debconf/config.dat
scyllaadm@ip-10-0-1-231:~$ 

[fruch]

Verified with https://jenkins.scylladb.com/job/scylla-master/job/releng-testing/job/next-machine-image/149/

scyllaadm@ip-10-0-1-231:~$ ls -la /var/cache/debconf/config.dat
-rw-r--r-- 1 root root 0 Jul 16 10:56 /var/cache/debconf/config.dat
scyllaadm@ip-10-0-1-231:~$ cat /var/cache/debconf/config.dat
scyllaadm@ip-10-0-1-231:~$ 

I would recommend merging on master, and testing the Azure upgrade test, that suffers from it, before we backport into all releases

[fruch]

LGTM