Merge pull request #3097 from QiJune/fix_bug_memory

fix bug in memory GetGPUBuddyAllocator

paddle/memory/memory.cc

@@ -60,6 +60,7 @@ detail::BuddyAllocator* GetGPUBuddyAllocator(int gpu_id) {
                                            platform::GpuMaxChunkSize());
     }
   }
+  platform::SetDeviceId(gpu_id);
   return as[gpu_id];
 }