gitignore google_apis/build more exclusively.

TBR=kjellander

Review URL: https://webrtc-codereview.appspot.com/819007

git-svn-id: http://webrtc.googlecode.com/svn/trunk@2793 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/.gitignore b/.gitignore
index 968e946..669d06f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,7 +32,7 @@
 .settings
 /build
 /chromium_deps
-/google_apis
+/google_apis/build
 /gyp-mac-tool
 /Makefile
 /out