Remove unused config.h and math.h includes.

BUG=1788
R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/18859004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/talk@6756 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/media/webrtc/webrtcvideoengine2.cc b/media/webrtc/webrtcvideoengine2.cc
index 12fcec0..e08f170 100644
--- a/media/webrtc/webrtcvideoengine2.cc
+++ b/media/webrtc/webrtcvideoengine2.cc
@@ -28,12 +28,6 @@
 #ifdef HAVE_WEBRTC_VIDEO
 #include "talk/media/webrtc/webrtcvideoengine2.h"
 
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include <math.h>
-
 #include <set>
 #include <string>