Gerrit sanity bot should not complain about cmake files added to the repo

Currently the sanity bot complains with something like:

Patch Set 1: Sanity problems found

tests/manual/cmake/pass(needsquoting)6/CMakeLists.txt:

• Warning: Adding alien build system file

This check should be relaxed or changed to a check for CMakeLists.txt.user files that creator creates.