logging: Make logger and log format configurable through cli

Change-Id: Ic4b701a6621578848ff67ae4ecb5a10b5f32f93b
BUG: 1075611
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-on: http://review.gluster.org/7372
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>