Fix error detection when starting kpropd/kadmind
    
    - drop a patch we're not applying
    - wrap kadmind and kpropd in scripts which check for the presence/absence
      of files which dictate particular exit codes before exec'ing the actual
      binaries, instead of trying to use ConditionPathExists in the unit files
      to accomplish that, so that we exit with failure properly when what we
      expect isn't actually in effect on the system (#800343)