Removes script for generating supplement.gypi also adds git ignore for tools/gn.

BUG=N/A
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/7299004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5403 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/.gitignore b/.gitignore
index aab8f75..bc2e478 100644
--- a/.gitignore
+++ b/.gitignore
@@ -83,6 +83,7 @@
 /tools/android
 /tools/android-dummy-test
 /tools/clang
+/tools/gn
 /tools/grit
 /tools/gritsettings
 /tools/gyp
@@ -94,7 +95,6 @@
 /webrtc/modules/audio_device/android/test/bin/
 /webrtc/modules/audio_device/android/test/gen/
 /webrtc/modules/audio_device/android/test/libs/
-/webrtc/supplement.gypi
 /webrtc/video_engine/test/android/bin
 /webrtc/video_engine/test/android/gen
 /webrtc/video_engine/test/android/libs