Expose locally collected rx peer statistics

Expose locally collected rx peer statistics

This implements rx_GetLocalPeers(), which exposes peer statistics
that are currently collected to the cache manager. This function
will later be used to rank both the file server and vldb server
lists using the statistics exposed by rx_GetLocalPeers().

Reviewed-on: http://gerrit.openafs.org/http://gerrit.openafs.org/186
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>