update benchmark (open-mmlab#891)

Author: yhcao6

configs/ms_rcnn/README.md

@@ -19,5 +19,6 @@
 | R-50-FPN      | caffe      | 2x      | -        | -                   | -              | 38.2   | 35.9    | [model](https://s3.ap-northeast-2.amazonaws.com/open-mmlab/mmdetection/models/ms-rcnn/ms_rcnn_r50_caffe_fpn_2x_20190525-a07be31e.pth) |
 | R-101-FPN     | caffe      | 1x      | 6.2      | 0.682               |  9.1           | 39.8   | 37.2    | [model](https://open-mmlab.s3.ap-northeast-2.amazonaws.com/mmdetection/models/ms-rcnn/ms_rcnn_r101_caffe_fpn_1x_20190624-677a5548.pth) |
 | R-101-FPN     | caffe      | 2x      | -        | -                   |  -             | 40.7   | 37.8    | [model](https://s3.ap-northeast-2.amazonaws.com/open-mmlab/mmdetection/models/ms-rcnn/ms_rcnn_r101_caffe_fpn_2x_20190525-4aee1528.pth) |
-| R-X101-64x4d  | pytorch    | 1x      | 10.5     | 1.214               |  6.4           | 42.2   | 39.2    | [model](https://s3.ap-northeast-2.amazonaws.com/open-mmlab/mmdetection/models/ms-rcnn/ms_rcnn_x101_64x4d_fpn_1x_20190525-026b16ae.pth) |
+| R-X101-32x4d  | pytorch    | 2x      | 7.6      | 0.844               |  8.0           | 41.7   | 38.5    | [model](https://open-mmlab.s3.ap-northeast-2.amazonaws.com/mmdetection/models/ms-rcnn/ms_rcnn_x101_32x4d_fpn_2x_20190628-ab454d07.pth) |
+| R-X101-64x4d  | pytorch    | 1x      | 10.5     | 1.214               |  6.4           | 42.0   | 39.1    | [model](https://open-mmlab.s3.ap-northeast-2.amazonaws.com/mmdetection/models/ms-rcnn/ms_rcnn_x101_64x4d_fpn_1x_20190628-dec32bda.pth) |
 | R-X101-64x4d  | pytorch    | 2x      | -       | -                    |  -             | 42.2   | 38.9    | [model](https://s3.ap-northeast-2.amazonaws.com/open-mmlab/mmdetection/models/ms-rcnn/ms_rcnn_x101_64x4d_fpn_2x_20190525-c044c25a.pth) |