Changed RPM output to be conditional.
Changed RPM output to be conditional.

Only output RPM macros if there is a VCS value. Otherwise the build
will fail with a macro error.

vladistan/autorevision,dak180/autorevision,dak180/autorevision,vladistan/autorevision,Autorevision/autorevision,Autorevision/autorevision,vladistan/autorevision,Autorevision/autorevision,dak180/autorevision