Remove USE_NINJA=false

And everything special-cased on that. Add a warning if USE_NINJA is
set to let users know that it no longer changes anything.

Change-Id: Ib8739151fe26ea6bf8f76b7ac2b8f4097dab0b47
diff --git a/core/phony_package.mk b/core/phony_package.mk
index 866b13c..b534335 100644
--- a/core/phony_package.mk
+++ b/core/phony_package.mk
@@ -7,7 +7,7 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
-$(LOCAL_BUILT_MODULE): $(LOCAL_MODULE_MAKEFILE_DEP) $(LOCAL_ADDITIONAL_DEPENDENCIES)
+$(LOCAL_BUILT_MODULE): $(LOCAL_ADDITIONAL_DEPENDENCIES)
 	$(hide) echo "Fake: $@"
 	$(hide) mkdir -p $(dir $@)
 	$(hide) touch $@