tests: metadata self-heal tests

Change-Id: Idef49b22018908c0a2ed95852b0670a91a750eba
BUG: 1132913
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/8515
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>