Bug 1756058 - Stop CalMetronome "hour" and "day" events at start-up. r=john.bieling

The events will fire if _lastFireTime is not initialised to the current time, because 0 is more than an hour/day ago.

Differential Revision: https://phabricator.services.mozilla.com/D139075

--HG--
extra : amend_source : 542dbd0b5fc73d35da1e52232ec7a24f7acb144a
extra : histedit_source : 1135c37ccd7903434d42082ad86f94bfa36c017e

calendar/base/src/CalMetronome.jsm

@@ -66,6 +66,7 @@ var CalMetronome = {
 
   init() {
     let now = new Date();
+    this._lastFireTime = now.valueOf();
     this._lastHour = now.getHours();
     this._lastDay = now.getDay();