Ignoring the BuildConfig from android as it's a generated file

Author: shs96c

.gitignore

@@ -20,6 +20,7 @@ iphone/src/objc/atoms.h
 /build/
 android/client/bin/
 android/server/bin/
+android/gen/org/openqa/selenium/android/app/BuildConfig.java
 android/gen/org/openqa/selenium/android/app/Manifest.java
 cpp/IEDriver/IEReturnTypes.h
 java/org/openqa/selenium/ie/IeReturnTypes.java