Fix string interpolation to delayed to be handled by the logging code
Fix string interpolation to delayed to be handled by the logging code

String interpolation should be delayed to be handled by the logging
code, rather than being done at the point of the logging call.
See the oslo i18n guideline.
* http://docs.openstack.org/developer/oslo.i18n/guidelines.html

Change-Id: If06663076e4081c6268ba88c157513723b734b31
Closes-Bug: #1596829

openstack/python-glanceclient,openstack/python-glanceclient