Fix dump-products.

m dump-products didn't print anything useful prior to this change,
however this was visible in the terminal:
15:18:58 Error dumping make vars: Failed to parse make line: "==== build/target/product/aosp_arm.mk ===="

Convert this goal to normal target instead, which apart from making
$(info) actually print something, considers the build successful
when running "m dump-products" too. This makes it easier to run with
e.g. multiproduct_kati.

Test: m dump-products
Change-Id: I944c87cd0fd323687690b0fcc3c37a8f37242cd9

core/main.mk

@@ -1435,6 +1435,11 @@ modules:
 	@echo "$(call module-names-for-tag-list,$(ALL_MODULE_TAGS))" | \
 	      tr -s ' ' '\n' | sort -u | $(COLUMN)
 
+.PHONY: dump-products
+dump-products:
+	$(dump-products)
+	@echo Successfully dumped products
+
 .PHONY: nothing
 nothing:
 	@echo Successfully read the makefiles.

core/product_config.mk

@@ -243,11 +243,6 @@ $(foreach makefile,$(ARTIFACT_PATH_REQUIREMENT_PRODUCTS),\
 # Sanity check
 $(check-all-products)
 
-ifneq ($(filter dump-products, $(MAKECMDGOALS)),)
-$(dump-products)
-$(error done)
-endif
-
 # Convert a short name like "sooner" into the path to the product
 # file defining that product.
 #