Don't crash if the ssh client is already dead

If the SSH client terminated abnormally in the background (e.g. the
server shutdown while we were doing a sync) then the pid won't exist.
Instead of crashing, ignore it, the result we wanted (a non-orphaned
ssh process) is already acheived.

Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed