Revert "Revert "emulator: create qemu images for system,vendor""

This reverts commit 9b99ddc8a58fc54c04a74b4a158bc06b90420f02.
and add syste-qemu.img to the dependency list of sdk target

Test: build sdk target successfully

Change-Id: Idb0bee56275f3bfe33ba7d29463e4b8e0699ec33
diff --git a/core/tasks/sdk-addon.mk b/core/tasks/sdk-addon.mk
index 610e0ce..e3bd47d 100644
--- a/core/tasks/sdk-addon.mk
+++ b/core/tasks/sdk-addon.mk
@@ -63,7 +63,7 @@
 
 # Files copied in the system-image directory
 files_to_copy += \
-	$(addon_dir_img):$(BUILT_SYSTEMIMAGE):images/$(TARGET_CPU_ABI)/system.img \
+	$(addon_dir_img):$(INSTALLED_QEMU_SYSTEMIMAGE):images/$(TARGET_CPU_ABI)/system.img \
 	$(addon_dir_img):$(BUILT_USERDATAIMAGE_TARGET):images/$(TARGET_CPU_ABI)/userdata.img \
 	$(addon_dir_img):$(BUILT_RAMDISK_TARGET):images/$(TARGET_CPU_ABI)/ramdisk.img \
 	$(addon_dir_img):$(PRODUCT_OUT)/system/build.prop:images/$(TARGET_CPU_ABI)/build.prop \