Updated openstack/openstack
Project: openstack/tempest  907ed711f265305316fdc80acd16e9657cb2c0b4

Fix error message when isolated tenant subnet creation fails

The current code assumes that setting the message of an exception will
cause the desired message to be displayed but this does not appear to be true.

Change-Id: I7e91179e7cb426645e9250671d3b54475f79a613