Update SDK files to API 12/Android 3.1

Change-Id: I630413dab4f6859623a9c1aa44b54abe6ef392b8
diff --git a/sdk/platform_source.properties b/sdk/platform_source.properties
index 6ea43dc..6be2cb1 100644
--- a/sdk/platform_source.properties
+++ b/sdk/platform_source.properties
@@ -1,6 +1,6 @@
-Pkg.Desc=Android SDK Platform 3.0
+Pkg.Desc=Android SDK Platform 3.1
 Pkg.UserSrc=false
-Platform.Version=3.0
+Platform.Version=3.1
 Pkg.Revision=1
-AndroidVersion.ApiLevel=11
-#AndroidVersion.CodeName=Honeycomb
+AndroidVersion.ApiLevel=12
+#AndroidVersion.CodeName=