Updated openstack/openstack
Project: openstack/oslo.db  b427eb4505bb416ce364caa8ff3f30380ff113a9

Improve error reporting for backend import failures

Use import_module instead of try_import so that any import exception
includes a full stack trace and the original error message.

Change-Id: I64449688f22a224b590807317472f26e64f377a3