Default host module tag to optional.

Change-Id: I8ae572b368e7ecdcc8e5bb257bb2f6084b5fb508
diff --git a/core/base_rules.mk b/core/base_rules.mk
index 9430532..c0b1c8d 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -57,9 +57,12 @@
 
 LOCAL_MODULE_TAGS := $(sort $(LOCAL_MODULE_TAGS))
 ifeq (,$(LOCAL_MODULE_TAGS))
+ifeq (,$(LOCAL_IS_HOST_MODULE))
 # Modules without tags fall back to user (which is changed to user eng below)
 LOCAL_MODULE_TAGS := user
-#$(warning default tags: $(lastword $(filter-out config/% out/%,$(MAKEFILE_LIST))))
+else
+LOCAL_MODULE_TAGS := optional
+endif
 endif
 
 # Only the tags mentioned in this test are expected to be set by module