support sles12sp3 servicenode installation

[bybai]

For #5417:
Before this fix, the xcatpostinit1.service will run with YaST2 Second Stage in parallel:

[  OK  ] Stopped wicked managed network interfaces.
         Starting wicked managed network interfaces...
[  OK  ] Started xcat service on compute nod...otscript and update node status.
[  OK  ] Started wicked managed network interfaces.
stty: 'standard input': unable to perform all requested operations
[  OK  ] Stopped Setup Virtual Console.
         Stopping Setup Virtual Console...
         Starting Setup Virtual Console...
[  OK  ] Started Setup Virtual Console.
[  OK  ] Started YaST2 Second Stage.
         Starting Autoyast2 Init Scripts...
         Starting Load kdump kernel and initrd...
[  OK  ] Started Autoyast2 Init Scripts.
         Starting Permit User Sessions...
[  OK  ] Started Permit User Sessions.
         Starting Hold until boot process finishes up...
         Starting Terminate Plymouth Boot Screen...

After code fix, the process is following,xcatpostinit1.service will run after Starting Autoyast2 Init Scripts, based on https://www.suse.com/documentation/sles-12/singlehtml/book_autoyast/book_autoyast.html#CreateProfile.Firstboot,

         Stopping wicked managed network interfaces...
[  OK  ] Stopped wicked managed network interfaces.
         Starting wicked managed network interfaces...
[  OK  ] Started wicked managed network interfaces.
stty: 'standard input': unable to perform all requested operations
[  OK  ] Stopped Setup Virtual Console.
         Stopping Setup Virtual Console...
         Starting Setup Virtual Console...
[  OK  ] Started Setup Virtual Console.
[  OK  ] Started YaST2 Second Stage.
         Starting Autoyast2 Init Scripts...
         Starting xcat service on compute no...script and update node status...
[  OK  ] Started Autoyast2 Init Scripts.
         Starting Permit User Sessions...
[  OK  ] Started Permit User Sessions.
         Starting Hold until boot process finishes up...
         Starting Terminate Plymouth Boot Screen...

Welcome to SUSE Linux Enterprise Server 12 SP3  (ppc64le) - Kernel 4.4.73-5-default (hvc0).
c910f03c09k13 login:

c910f03c09k13:~ # tail -f /var/log/xcat/xcat.log
+ [[ sles12.3 != sles11* ]]
+ service network stop
+ '[' 1 = 1 ']'
+ set +x
Tue Jul 24 07:19:23 EDT 2018 [info]: xcat.xcatinstallpost: Running /xcatpost/mypostscript.post
Tue Jul 24 07:19:23 EDT 2018 [info]: xcat.mypostscript: Running postbootscript: otherpkgs
Tue Jul 24 07:20:21 EDT 2018 [info]: xcat.mypostscript: postbootscript otherpkgs return with 0
Tue Jul 24 07:20:21 EDT 2018 [debug]: xcat.mypostscript: node booted, reporting status...
Tue Jul 24 07:20:21 EDT 2018 [info]: xcat.mypostscript: provision completed.(c910f03c09k13)
Tue Jul 24 07:20:21 EDT 2018 [info]: xcat.xcatinstallpost: /xcatpost/mypostscript.post return

[xcatbot]

CI CHECK RESULT : > PR FORMAT CORRECT> BUILD SUCCESSFUL > INSTALL XCAT SUCCESSFUL> CODE SYNTAX CORRECT> FAST REGRESSION TEST Successful: Totalcase 215 Passed 215 Failed 0

[immarvin]

i am ok with the change, merge to verify under automation