LU-2083 build: install git commit hooks automatically

Fix for previous commit http://review.whamcloud.com/4175

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: I014455aa4e73b7a384356c8d6e65f3feb28e7e1c
Reviewed-on: http://review.whamcloud.com/5494
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>