when watchdogd is asked to exit nicely (via SIGTERM) it will
stop timer. since watchdogd rc.d script is marked as 'shutdown'
it will exit (on shutdown) and stop timer. if system happens to
hung after watchdogd exited, manual reset is required. when one
operates in "lights-out" type of environments and without
readily available "remote hands" it could create a problem.

this provides ability to override "stop signal" for watchdogd.
default behavior is preserved, i.e. watchdogd will still be killed
via SIGTERM and timer will be stopped. in order to activate new
feature, one needs to put

watchdogd_sig_stop="KILL"

into /etc/rc.conf and also make sure watchdogd timeout is set
to long enough value allowing system to come back online before
timeout fires.

Obtained from:	Netflix
MFC after:	1 week