Do not use a user tag on apps, as it is ignored.

The build system does not honor user tags on apps,
and setting it is misleading.

This removes the confusion by making the makefiles
behave like they read.

Change-Id: I7c5feba1c7d07f915b97dd098584f29938a4c885
diff --git a/opengl/tests/gldual/Android.mk b/opengl/tests/gldual/Android.mk
index e73c249..995a5d7 100644
--- a/opengl/tests/gldual/Android.mk
+++ b/opengl/tests/gldual/Android.mk
@@ -11,7 +11,7 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
-LOCAL_MODULE_TAGS := user
+LOCAL_MODULE_TAGS := optional
 
 LOCAL_SRC_FILES := $(call all-subdir-java-files)