Updated openstack/openstack
Project: openstack/cinder  e1abba614668b3a8bbcdc0670e08109569d279d7

Log an error on nfs mount failure

Change from a log warning to a log error when an nfs driver
cannot mount the backend share. Add tests to ensure the error is
logged correctly.

Change-Id: Id9d51aebe349e7a4e09d1211b17efd8d47af97f5