OmniStoreInstaller: move to system_ext

Change-Id: Ide20e63f8911eaf34972922c8aceaca3868facf8
diff --git a/prebuilt/app/OmniStore/Android.mk b/prebuilt/app/OmniStore/Android.mk
index cf95385..fa46df9 100644
--- a/prebuilt/app/OmniStore/Android.mk
+++ b/prebuilt/app/OmniStore/Android.mk
@@ -6,6 +6,6 @@
 LOCAL_MODULE_CLASS := APPS
 LOCAL_MODULE_TAGS := optional
 LOCAL_CERTIFICATE := PRESIGNED
-LOCAL_MODULE_PATH  := $(TARGET_OUT_APPS)
 LOCAL_DEX_PREOPT := false
+LOCAL_SYSTEM_EXT_MODULE := true
 include $(BUILD_PREBUILT)