mgmt/glusterd: Make sure peerinfo->uuid_str is assigned

Change-Id: I9e2743ab61c8baee92a1dfd376ec4bb145776176
BUG: 963524
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/5016
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>