Fix swift example conf for keystoneauth changes

The previous swift proxy-server.conf example referred to
keystoneauth as it worked previous when it was coming from
the keystone repo. This patch changes it to match the sample
conf in the swift repo.

fixes bug 1092716

Change-Id: Ic658ef1c96a84cfc75698b9a7ef50d7724fd0ccb
Merge "Fix swift example conf for keystoneauth changes"