Bug fix: Thinning API was not updated after changing the scheduler callback signature

We recently changed the signature of the on_minibatch_begin() callback
from the scheduler (added 'meta') and the callback client
in the thinning module was not updated.

distiller/thinning.py

@@ -386,7 +386,7 @@ class FilterRemover(ScheduledTrainingPolicy):
             self.thinning_func(model, zeros_mask_dict, self.arch, self.dataset, optimizer=optimizer)
             self.done = True
 
-    def on_minibatch_begin(self, model, epoch, minibatch_id, minibatches_per_epoch, zeros_mask_dict, optimizer):
+    def on_minibatch_begin(self, model, epoch, minibatch_id, minibatches_per_epoch, zeros_mask_dict, meta, optimizer):
         # We hook onto the on_minibatch_begin because we want to run after the pruner which sparsified
         # the tensors.  Pruners configure their pruning mask in on_epoch_begin, but apply the mask
         # only in on_minibatch_begin