orchestra/daemon/cephadmunit: ignore exception when sending signal
orchestra/daemon/cephadmunit: ignore exception when sending signal

The osd thrashing is sending lots of signals (sighup) and can easily race with
a daemon shutting down entirely.

This makes us match the behavior of the original state.py signal() method.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

ceph/teuthology,ktdreyer/teuthology,ktdreyer/teuthology,ceph/teuthology