Apache reverse proxy implementation for keystone

The reverse proxy is used to implement CORS headers for now. Later the same
implementation can be used to enable ssl (just wanted to enable ssl as separate
patch).

This one depends on PR jiocloud/puppet-keystone#3
Fixed spec test failures
Fixed wrong admin_url in rjil::tempest

Removed version string from admin_url for keystone_config in rjil::tempest
Merge pull request #269 from hkumarmk/keystone_reverse_proxy

Apache reverse proxy implementation for keystone