default numGarbage to zero

Fixes a toontown crash when you exit

direct/src/showbase/GarbageReport.py

@@ -37,6 +37,7 @@ class GarbageReport(Job):
                                 findCycles=findCycles, doneCallback=doneCallback)
         self._printing = False
         jobMgr.add(self)
+        self.numGarbage = 0
 
     def run(self):
         # do the garbage collection