Remove the check for the local wmc-dist-patch script.

It is not shipped with the wmc-rest based projects source code. It gets included only during RPM build time and therefore we can't nicely use it like the https://cms-http-group.web.cern.ch/cms-http-group/tutorials/environ/rpm-dev.html instructions tell. This check was only there because sitedb used  to have its own dist-patch script.