Update keystone wsgi httpd script for oslo logging

When updating to the oslo logging module, it appears that this script
was missed, and erroneously still references .DEBUG, which is not
available in the oslo logging module.  This commit corrects the issue
and updates the reference to oslo log module to not be aliased to
"logging".

The extra logic to set the debug on the instantiated logger is still
needed to ensure all logging is seen (startup config logging, etc).

fixes-bug: 1220012
Change-Id: If5b4f9f28cb9d05f914848cbdb54b10c2c5f3b2d
Merge "Update keystone wsgi httpd script for oslo logging"