Bug 728294 will reduce false positives, but isn't ready yet. The sheriffs are being driven up the wall with the current MAX_LEAK_COUNT of 3 (ie https://bugzilla.mozilla.org/showdependencytree.cgi?id=754804&hide_resolved=1), it should be raised to 4 for now.

We were still getting lots of orange from the leaks that are already filed (& being ignored until bug 728294 lands), so bumped to 5: https://hg.mozilla.org/integration/mozilla-inbound/rev/d1b5e2bca3d6 (This failure always takes ages for TBPL to generate the summary, due to multiple bzapi calls, so is a real PITA for sheriffs). Ideally we'd switch the ShutdownLeakLogger to use a whitelist, but not worth it if bug 728294 is going to replace it with something completely different soon.