Add OVERRIDE_PACKAGES support for prebuild modules.

So that some prebuild module can override existing packages.

Change-Id: I4f0d019e07b84d24cf0234903bd4b06104e0ed27
diff --git a/core/prebuilt.mk b/core/prebuilt.mk
index 1bb3acf..b2bb07c 100644
--- a/core/prebuilt.mk
+++ b/core/prebuilt.mk
@@ -26,6 +26,8 @@
   prebuilt_module_is_a_library :=
 endif
 
+PACKAGES.$(LOCAL_MODULE).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
+
 # Ensure that prebuilt .apks have been aligned.
 ifneq ($(filter APPS,$(LOCAL_MODULE_CLASS)),)
 $(LOCAL_BUILT_MODULE) : $(LOCAL_PATH)/$(LOCAL_SRC_FILES) | $(ZIPALIGN)
@@ -51,7 +53,6 @@
 
 PACKAGES.$(LOCAL_MODULE).PRIVATE_KEY := $(LOCAL_CERTIFICATE).pk8
 PACKAGES.$(LOCAL_MODULE).CERTIFICATE := $(LOCAL_CERTIFICATE).x509.pem
-PACKAGES.$(LOCAL_MODULE).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
 PACKAGES := $(PACKAGES) $(LOCAL_MODULE)
 
 endif