Get suspends from logind to ignore watchdog then

[jmerdich]

On every resume, the watchdog thread happily reports that there has been a deadlock since the canary hasn't responded since before the computer resumed. Get notifications from logind over dbus to tell when suspend happens and ignore the one watchdog violation that might happen then.

On start-suspend, this ignores a single timeout indefinitely. On resume, that ignore gets a timeout of 2 seconds in the future (configurable), if it hasn't already been tripped. At any point if a real deadlock occurs, it will take a max of two watchdog periods to recognize it. If the configurable timeout is zero, no ignores happen and the extra dbus work is skipped.

This code is not Y2038 safe... but neither is the old code.

Addresses #13, which has apparently been around for almost 10 years in some form.

[melvyn2]

Annoying that this has been open for almost a year, especially for such a simple fix.