Fix bug: COMBINEALL should add extra prefix to avoid pid conflictions (#447)

Author: hsfzxjy

Diff for: fastreid/data/datasets/bases.py

@@ -102,8 +102,8 @@ def _combine_data(data):
             for img_path, pid, camid in data:
                 if pid in self._junk_pids:
                     continue
-                pid = self.dataset_name + "_" + str(pid)
-                camid = self.dataset_name + "_" + str(camid)
+                pid = self.dataset_name + "_test_" + str(pid)
+                camid = self.dataset_name + "_test_" + str(camid)
                 combined.append((img_path, pid, camid))
 
         _combine_data(self.query)