Rename is_unbundled_app_build and UNBUNDLED_APP_BUILD to TARGET_BUILD_APPS.

Change-Id: I79e6f60e009dad3a48709962347441e4ca0c337a
diff --git a/core/envsetup.mk b/core/envsetup.mk
index f8a2027..86aa2f3 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -342,6 +342,7 @@
 $(info   TARGET_BUILD_VARIANT=$(TARGET_BUILD_VARIANT))
 $(info   TARGET_SIMULATOR=$(TARGET_SIMULATOR))
 $(info   TARGET_BUILD_TYPE=$(TARGET_BUILD_TYPE))
+$(info   TARGET_BUILD_APPS=$(TARGET_BUILD_APPS))
 $(info   TARGET_ARCH=$(TARGET_ARCH))
 $(info   HOST_ARCH=$(HOST_ARCH))
 $(info   HOST_OS=$(HOST_OS))