.gitignore: + /third_party/{clang_format,usrcsctp}

clang_format and usrcsctp are both synced in through gclient and should
be suppressed.

BUG=
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/8159004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5532 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/.gitignore b/.gitignore
index 9778005..8a12a3d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -53,6 +53,7 @@
 /third_party/android_testrunner
 /third_party/android_tools
 /third_party/asan
+/third_party/clang_format
 /third_party/cygwin
 /third_party/directxsdk
 /third_party/expat
@@ -77,6 +78,7 @@
 /third_party/opus
 /third_party/protobuf
 /third_party/sqlite
+/third_party/usrsctp
 /third_party/valgrind
 /third_party/winsdk_samples/src
 /third_party/yasm