Bug 825820 - Call WarningsDatabase.prune at the end of Build(). r=gps.

--HG--
extra : rebase_source : aefe3d3e1e3f5edacbb83bb0c44031c1cfb200a1

python/mozbuild/mozbuild/mach_commands.py

@@ -57,6 +57,8 @@ class Build(MachCommandBase):
             {'count': len(warnings_collector.database)},
             '{count} compiler warnings present.')
 
+        warnings_database.prune()
+
         warnings_database.save_to_file(warnings_path)
 
         return status