remove kernel-source rpm after guest additions built
fix check for success of vbox guest additions installation
strip some nice-to-have packages to reduce footprint

Of course emacs is totally awesome, but we really want this
to be as small as possible :-(  It can always be installed
later.  Similarly with other packages.
patch crmsh to fix bnc#877484

https://bugzilla.novell.com/show_bug.cgi?id=877484