Support dist-ing the userdatatarball

So that we can get to the contents of userdata from the build server
without extracting the image.

Bug: 27719200
Test: m userdatatarball dist
(cherry-picked from 69af2e4102d3af3f5f06e4d7a615d42dbb3446bb)

Change-Id: I1438597bd29df80665571f7dc3b4957b9adde870
diff --git a/core/Makefile b/core/Makefile
index 2031132..7676a4f 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1383,6 +1383,8 @@
 $(INSTALLED_USERDATATARBALL_TARGET): $(FS_GET_STATS) $(INTERNAL_USERDATAIMAGE_FILES)
 	$(build-userdatatarball-target)
 
+$(call dist-for-goals,userdatatarball,$(INSTALLED_USERDATATARBALL_TARGET))
+
 .PHONY: userdatatarball-nodeps
 userdatatarball-nodeps: $(FS_GET_STATS)
 	$(build-userdatatarball-target)