moxi goes 100% cpu and spammy when all vbuckets are dead

moxi spin-loops retrying commands against all servers for a vbucket if that vbucket is in dead state on all servers.

There should probably be some give-up timeout or max-retries.

Or, if # of retries > # of servers, then we've gone all around the the server-list without and owner, so that's probably a natural place to error back to the client connection.