SimpleMessenger: remove void send_keepalive.
SimpleMessenger: remove void send_keepalive.

Nobody uses this; they all call the version that returns an int.

Signed-off-by: Greg Farnum <0bcb4295d38ee745130ea5f2bb88ef4eef474e61@dreamhost.com>

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph