glusterd/snapshot : Fix for snap create preval for remote peer err msg

Fix for the snap create prevalidation error collation when remote peer failed.

Change-Id: If9563580eae4d9bc4d4d795f0b434f2c85b94007
BUG: 1101993
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/7899
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijaikumar Mallikarjuna <vmallika@redhat.com>
Reviewed-by: Kaushal M <kaushal@redhat.com>