Configure glance-cache.conf with swift backend

glance::backend::swift was not properly configuring
swift_store_* in /etc/glance/glance-cache.conf
when using swift backend.

Change-Id: I7b46dd2bd1ff050759b11cbc9c3c7068e4c3e01e
Configure glance-cache.conf with file backend

glance::backend::file was not properly configuring
filesystem_store_datadir in /etc/glance/glance-cache.conf
when using file backend.

Change-Id: Ie8d3259de429089f2f00fbafd2e5cbf90c069263
Merge "Configure glance-cache.conf with swift backend"
Merge "Configure glance-cache.conf with file backend"