Don't give the user tag to host modules automatically.

Change-Id: I12d0a84786e5bf2224efd8684526b6097e6105d7
diff --git a/core/definitions.mk b/core/definitions.mk
index c1757f3..6e87cc1 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -55,6 +55,11 @@
 # its sub-variables.)
 ALL_MODULE_NAME_TAGS:=
 
+# All host modules are automatically installed (i.e. outside
+# of the product configuration scheme).  This is a list of the
+# install targets (LOCAL_INSTALLED_MODULE).
+ALL_HOST_INSTALLED_FILES:=
+
 # Full paths to all prebuilt files that will be copied
 # (used to make the dependency on acp)
 ALL_PREBUILT:=