This makes keystone use the proxy uwsgi module when running in uwsgi
mode. It also introduces a new stackrc variable which is WSGI_MODE
that we can use to control the conditionals in services that current
work with mod_wsgi.
Also update retry timeouts on proxy pass so that workers don't disable
their connections during polling for initial activity.
Change-Id: I46294fb24e3c23fa19fcfd7d6c9ee8a932354702
6ed53156b6