Avoid useless processes launching shell

There's no reason to keep 3 shell processes to execute one.
Remove "()" in command to avoid one additional process.
Add "exec" on last command to replace current process.
Remove exports, not necessary as changing one single command
environment.

This changes this:

$ pstree -alp | grep -4 bash
...
  |-python,2051 /usr/lib64/xsconsole/XSConsole.py -f root
  |   `-sh,3238 -c ( export HOME=/root; export TMOUT=300 && cat /etc/motd && /bin/bash --login )
  |       `-sh,3239 -c ( export HOME=/root; export TMOUT=300 && cat /etc/motd && /bin/bash --login )
  |           `-bash,3241 --login
...

to this:

$ pstree -alp | grep -4 bash
...
  |-python,2044 /usr/lib64/xsconsole/XSConsole.py -f root
  |   `-bash,3128 --login
...

Signed-off-by: Frediano Ziglio <[email protected]>

plugins-base/XSFeatureLocalShell.py

@@ -32,7 +32,7 @@ def StartLocalShell(self):
         user = os.environ.get('USER', 'root')
         Layout.Inst().ExitBannerSet(Lang("\rShell for local user '")+user+"'.\r\r"+
                 Lang("Type 'exit' to return to the management console.\r"))
-        Layout.Inst().SubshellCommandSet("( export HOME=/root; export TMOUT="+str(State.Inst().AuthTimeoutSeconds())+" && cat /etc/motd && /bin/bash --login )")
+        Layout.Inst().SubshellCommandSet("cat /etc/motd && HOME=/root TMOUT="+str(State.Inst().AuthTimeoutSeconds())+" exec /bin/bash --login")
         XSLog('Local shell')
 
     @classmethod