scap backport: Also allow /r/c/ change URLs
This is the format produced by {{gerrit}} / {{deploy}} on Deployments, so it’s annoying if it isn’t recognized by scap.
Change-Id: I951a52a5b72077b301cbd3f18fdc90f8dfa3e72a
Completely untested – I added it to the unit tests and am relying on CI :P