Bug 1411690 - Floor the repair advance and most recent repair timestamps. r=tcsc

The timestamps are automatically truncated when they're stored in
prefs, which is fine because we don't need millisecond precision.
However, the truncation raises a warning, so we need to explicitly
floor the values.

MozReview-Commit-ID: BRflL6s0b1

--HG--
extra : rebase_source : 6724a1ad05cb8aee4ab8c666545784960c23a0f3

services/sync/modules/doctor.js

@@ -82,7 +82,7 @@ this.Doctor = {
           }
         }
       } finally {
-        this.lastRepairAdvance = this._now();
+        this.lastRepairAdvance = Math.floor(this._now());
       }
     }
   },