Move plugin_core.jar back to Launcher3 to unblock code merge

Change-Id: Ic9d6ab16ac7a8c5c1f528bdcac06e56f718a3f91
diff --git a/Android.mk b/Android.mk
index 25593e6..b3b1c82 100644
--- a/Android.mk
+++ b/Android.mk
@@ -16,6 +16,15 @@
 
 LOCAL_PATH := $(call my-dir)
 
+include $(CLEAR_VARS)
+LOCAL_MODULE := libPluginCore
+LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE_CLASS := JAVA_LIBRARIES
+LOCAL_SRC_FILES := libs/plugin_core.jar
+LOCAL_UNINSTALLABLE_MODULE := true
+LOCAL_SDK_VERSION := current
+include $(BUILD_PREBUILT)
+
 #
 # Build rule for plugin lib (needed to write a plugin).
 #