Fix VCM test build warnings on Mac with clang.

BUG=
TEST=

Review URL: http://webrtc-codereview.appspot.com/318008

git-svn-id: http://webrtc.googlecode.com/svn/trunk@1160 4adac7df-926f-26a2-2b94-8c16560cd09d

src/modules/video_coding/main/test/mt_test_common.cc

@@ -14,6 +14,7 @@
 
 #include "rtp_dump.h"
 
+namespace webrtc {
 
 TransportCallback::TransportCallback(webrtc::RtpRtcp* rtp,
                                      const char* filename):
@@ -130,3 +131,5 @@ bool TransportThread(void *obj)
     state->_transport.TransportPackets();
     return true;
 }
+
+}  // namespace webrtc