find-copyrights.pl: updates for git

And minor whitespace cleanup.

(cherry picked from commit a12eef6ecf7d5d1164cd66047913ba6139fbaccf)
gkcommit.pl: so long gkcommit; you served us well in SVN days...

(cherry picked from commit f72bf3b3c341152455fdff2aa9dc98d05718db3d)