Currently, the only time that users can set watchdog action is at
the start as all we expose is this -watchdog-action command line
argument. This is suboptimal when users want to plug the device
later via monitor. Alternatively, they might want to change the
action for already existing device on the fly.

Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1447169Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Message-Id: <35d6ce6fe3d357122d73b8272bc8198134c74104.1504771369.git.mprivozn@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
[Missing colon in doc comment fixed]
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>