LU-3434 build: disable automatic Git hook install

Don't automatically install the Git commit hooks for checking code
and commit message style into .git/hooks/{prepare-,}commit-msg.
This should be done manually by the developer and/or checked when
the patch is pushed to Gerrit.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Ie44be3baa5f04eb71a3d7f76556c455fd5fa7052
Reviewed-on: http://review.whamcloud.com/7046
Reviewed-by: Ned Bass <bass6@llnl.gov>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Christopher J. Morrone <chris.morrone.llnl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>