Fix kwargs parameter missing error in two_stage (open-mmlab#6256)

Author: pingguokiller

Diff for: mmdet/models/detectors/two_stage.py

@@ -138,7 +138,8 @@ def forward_train(self,
                 gt_bboxes,
                 gt_labels=None,
                 gt_bboxes_ignore=gt_bboxes_ignore,
-                proposal_cfg=proposal_cfg)
+                proposal_cfg=proposal_cfg,
+                **kwargs)
             losses.update(rpn_losses)
         else:
             proposal_list = proposals

Diff for: mmdet/models/roi_heads/standard_roi_head.py

@@ -58,7 +58,8 @@ def forward_train(self,
                       gt_bboxes,
                       gt_labels,
                       gt_bboxes_ignore=None,
-                      gt_masks=None):
+                      gt_masks=None,
+                      **kwargs):
         """
         Args:
             x (list[Tensor]): list of multi-level img features.