ubuntu: Fix openssh postinst call in >= saucy

The new openssh uses a different mechanism to start/stop the daemon
which in turn requires a few tweaks in our template to deal with both
the new and old ways of doing that.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>