glusterd: print the peer name instead of a null UUID in a rpc failure message

This patch improves the failure message by printing the correct peer name
instead of a blank uuid in case of rpc connection is lost/broken.

Change-Id: Ia232792051f23896883b239982cb48130e3ce60e
BUG: 1146902
Signed-off-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-on: http://review.gluster.org/8597
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Kaushal M <kaushal@redhat.com>