[rtp_rtcp] fixed namespaces lint warnings

webrtc/modules/rtp_rtcp/source/vp8_partition_aggregator.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 247 matching lines @@
       num_fragments = n;
       best_cost = cost;
     }
   }
   assert(num_fragments > 0);
   // TODO(mflodman) Assert disabled since it's falsely triggered, see issue 293.
   // assert(large_partition_size / num_fragments + 1 <= max_payload_size);
   return num_fragments;
 }
 
-}  // namespace
+}  // namespace webrtc