This PR resolves an issue where the `/metrics` endpoints exposed by the proxy were not returning metrics of the etcd members servers but of the proxy itself.
Signed-off-by: Sam Batschelet <sbatsche@redhat.com>
groupcache needs a write lock and has no way to expire keys; ccache can
do this, though.
Also removes the key count metric, since there's no way to efficiently
calculate it using ccache.
Gyuho Lee