Revert a local change that isn't be ready yet -- need tinderboxen doing leak tests before we can actually make this change, sigh.

testing/mochitest/runtests.py.in

@@ -162,7 +162,7 @@ class MochitestOptions(optparse.OptionParser):
                            "refcounted objects (or bytes in classes with "
                            "MOZ_COUNT_CTOR and MOZ_COUNT_DTOR) is greater "
                            "than the given number")
-    defaults["leakThreshold"] = 0
+    defaults["leakThreshold"] = -1
 
     # -h, --help are automatically handled by OptionParser