JACK_APPS_VERSION defines Jack version used to build apps

Bug: 26897554

Change-Id: Ic9effc484506d7c13255e0560c1b717d3233ba26
diff --git a/tools/jack_versions.mk b/tools/jack_versions.mk
index 5248cfc..f076727 100644
--- a/tools/jack_versions.mk
+++ b/tools/jack_versions.mk
@@ -24,6 +24,7 @@
 ifeq ($(JACK_DEFAULT_VERSION),)
 $(error "$(ANDROID_JACK_DEFAULT_VERSION)" is an invalid value for ANDROID_JACK_DEFAULT_VERSION)
 endif
+JACK_APPS_VERSION := $(JACK_DEFAULT_VERSION)
 else
 ifneq (,$(TARGET_BUILD_APPS))
 # Unbundled branches
@@ -32,4 +33,5 @@
 # Complete android tree
 JACK_DEFAULT_VERSION := $(JACK_STABLE_VERSION)
 endif
+JACK_APPS_VERSION := $(JACK_DOGFOOD_VERSION)
 endif