mgmt/glusterd: Out of bounds access to fs_info struct

Change-Id: Ifa0d4ac17f9da94660a7b7f567a0f07b5cec7aec
BUG: 1164775
Signed-off-by: Petr Medonos <petr.medonos@etnetera.cz>
Reviewed-on: http://review.gluster.org/9138
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-by: Kaushal M <kaushal@redhat.com>