Redo the templates generation and installation.

Redo the templates generation and installation.

Per discussion with people interested in binary packaging,
change the default template location from /etc/git-core to
/usr/share/git-core hierarchy.  If a user wants to run git
before installing for whatever reason, in addition to adding
$src to the PATH environment variable, git-init-db can be run
with --template=$src/templates/blt/ parameter.

Signed-off-by: Junio C Hamano <junkio@cox.net>