CtsShim: Support building with tapas

This way the build server can build these apks, instead of the manual
process that was described in the README.

Bug: 29122339
Change-Id: I2d3d9924da908d501d3b1b07b4a317f8ad6f413f
diff --git a/packages/CtsShim/Android.mk b/packages/CtsShim/Android.mk
index cd5b288..fa6423e 100644
--- a/packages/CtsShim/Android.mk
+++ b/packages/CtsShim/Android.mk
@@ -53,3 +53,4 @@
 
 include $(BUILD_PREBUILT)
 
+include $(call all-makefiles-under,$(LOCAL_PATH))