Fix art-boot-image rule.

The default boot image variable name has changed.

Bug: 129014050
Test: m art-boot-image
Change-Id: Icfa508cf6bc210e56aa4ab86b19e8d9f7f459a39
diff --git a/Android.mk b/Android.mk
index 76965d2..6917cb5 100644
--- a/Android.mk
+++ b/Android.mk
@@ -682,11 +682,11 @@
 # Can be used, for example, to dump initialization failures:
 #   m art-boot-image ART_BOOT_IMAGE_EXTRA_ARGS=--dump-init-failures=fails.txt
 .PHONY: art-boot-image
-art-boot-image: $(DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME)
+art-boot-image:  $(DEXPREOPT_IMAGE_boot_$(TARGET_ARCH))
 
 .PHONY: art-job-images
 art-job-images: \
-  $(DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME) \
+  art-boot-image \
   $(2ND_DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME) \
   $(HOST_OUT_EXECUTABLES)/dex2oats \
   $(HOST_OUT_EXECUTABLES)/dex2oatds \