ceph: prevent dup stale messages to console for restarting mds

Prevent duplicate 'mds0 caps stale' message from spamming the console every
few seconds while the MDS restarts.  Set s_renew_requested earlier, so that
we only print the message once, even if we don't send an actual request.

Signed-off-by: Sage Weil <sage@newdream.net>