Barrier: Barrier translator options configuration

barrier enable/disable, barrier-timeout configuration in barrier translator.

Change-Id: I7cbf9cd4f5e55d42dcc6b7cd6827234566c7b6f3
BUG: 1060002
Signed-off-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-on: http://review.gluster.org/7177
Reviewed-by: Kaushal M <kaushal@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>