CMakeGitInfo does not run properly from downloaded zip file

[paulmking]

Environment: (where does this bug occur, have you tried other environments)

• branch (master for latest released): master
• revision (HEAD for most recent): head
• OS or system: Ubuntu
• Special ROOT or Geant4 versions?

Steps to reproduce: (give a step by step account of how to trigger the bug)

1. Create a build directory in a copy of japan from the zip file
2. execute "cmake .."

Expected Result: (what do you expect when you execute the steps above)

The gitinfo.cc file will be generated in the build directory

Actual Result: (what do you get when you execute the steps above)

The gitinfo.cc file is not generated.