Updated openstack/openstack
Project: openstack/nova  79dd1243263cc6933ee6d22572e989f84acd1799
null
Fix exception message being changed by nested exception

Minor change to avoid having the error message changed in the
_build_instance exception handler if an exception occurs during
network cleanup.

Change-Id: Ica7afc76f1fd261541ff9cf03b6c5e079e9404f8