LU-930 misc: update README path to git hooks

Update the README file so that the paths given to the git hooks stored
in contrib are current.

Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Change-Id: If864751d88ad54de629a1cda9d1ba6f2089ecd69
Reviewed-on: http://review.whamcloud.com/13428


Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>