Packaging gitolite for debian requires the rc file to be in /etc/gitolite.
But non-root installs must still be supported, and they need it in $HOME.
This means the rc file is no longer in a fixed place, which needs code to find
the rc file first. See comments inside new file 'gitolite.pm' for details.
The rest of the changes are in the other programs, to replace the hard-coded
rc filename with a call to this new code.
