Fix NPE in icon check

Fix for
http://code.google.com/p/android/issues/detail?id=27966

Change-Id: I1a3e538644044ee0c02cb729aca40e15f5b23d22
diff --git a/.gitignore b/.gitignore
index 80b6f7c..019a6f1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 *.pyc
 Thumbs.db
 *.class
+*.DS_Store
 testapps/testSensors/proguard.cfg
 
 # Hide temporary files created by the build_server script