Bug 1593537 - Update minimonths when the start of week pref or the week numbers pref changes; r=pmorris

--HG--
extra : rebase_source : 46114b3f5bb4489ca93e33bb17a5399d0c0cd87d
extra : amend_source : 68cd013451b964d39ad15251d53d5f581a6b8ff6

calendar/base/content/widgets/calendar-minimonth.js

@@ -466,6 +466,7 @@
       switch (aData) {
         case "calendar.week.start":
         case "calendar.view-minimonth.showWeekNumber":
+          delete this.mDayMap; // Days have moved, force a refresh of the grid.
           this.refreshDisplay();
           break;
       }