Remove unused and deprecated auth-context filter

keystone.middleware.auth_token is now just aliased to
keystoneclient.middleware.auth_token.

Also heat_auth_token doesn't seem to exist, so this has likely
always been broken

Change-Id: I5eadd9a02e41921b39fc8b6783c22010893bb5e9
Remove paste config for non-existant cache filters

This appears to be junk DNA from glance, which has filters
for caching image files.

Change-Id: Id7ae29028d351dd005a61a5727bc7d40ceb0a705
Merge "Remove unused and deprecated auth-context filter"
Merge "Remove paste config for non-existant cache filters"