Add i18n _ import to cimc common

For some reason this wasn't picked up by pep8 checks or any unit tests
importing the module, even in system testing this didn't cause any
problems. However trying to import this module from another piece of
python outside of ironic, flagged that common didn't import the _
function.

Change-Id: Ide9d79095ba4486359c91f3127f6df8d9576245c
Closes-Bug: #1499284

ironic/drivers/modules/cimc/common.py

@@ -18,6 +18,7 @@ from oslo_log import log as logging
 from oslo_utils import importutils
 
 from ironic.common import exception
+from ironic.common.i18n import _
 from ironic.drivers.modules import deploy_utils
 
 REQUIRED_PROPERTIES = {