The changes made on 21 May on this file (1) break the compatibility of Caffe and RCNN. I don't understand why they needed to take place and the documentation does not mention them either. By putting the caffe mex file into a private folder, it is not accessible any more. See for example (2). These changes should be undone!
(1) https://github.com/BVLC/caffe/commits/master/matlab/%2Bcaffe/private/caffe_.cpp
(2) https://github.com/rbgirshick/rcnn/blob/master/rcnn_load_model.m