fix gdr compiling error (tensorflow#12462)

Author: byronyi

tensorflow/contrib/gdr/gdr_memory_manager.h

@@ -16,14 +16,9 @@ limitations under the License.
 #ifndef GDR_MEMORY_MANAGER_H_
 #define GDR_MEMORY_MANAGER_H_
 
+#include "google/protobuf/any.pb.h"
 #include "tensorflow/core/lib/core/status.h"
 
-namespace google {
-namespace protobuf {
-class Any;
-}
-}
-
 namespace tensorflow {
 
 class Device;