Fix the skipException message to follow a pattern similar to other messages
Fix the skipException message to follow a pattern similar to other messages

Removed the period at the end of skip exception message because this is the
only message that appears different from any other cinder related exceptions

Change-Id: I28dacd001a62a2275a1e068e59066b0cdaaf98d3

cisco-openstack/tempest,openstack/tempest,masayukig/tempest,cisco-openstack/tempest,openstack/tempest,masayukig/tempest