Fix finding the maps.jar archive

The current -path value passed to find will ignore all the APIs older than 16. The addon path
format used before 16 is

  addon-google_apis-google_inc_-X

while with 16 and up it is

  addon-google_apis-google-X

The patch uses -regex instead of -path to cope with the above.
Merge pull request #3 from mono/fix-maps-build

Fix finding the maps.jar archive