Missed one part of removing the vbox target.

Change-Id: I8edb5252b5e71de042b79cb9eb2a497d89efb773
(cherry picked from commit bfbd41edcb2b092cd27bc57647f4d53de0b0df54)
diff --git a/core/Makefile b/core/Makefile
index d39ac9c..11ae7f5 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1220,12 +1220,6 @@
 endif # BOARD_VENDORIMAGE_FILE_SYSTEM_TYPE
 
 # -----------------------------------------------------------------
-# bring in the installer image generation defines if necessary
-ifeq ($(TARGET_USE_DISKINSTALLER),true)
-include bootable/diskinstaller/config.mk
-endif
-
-# -----------------------------------------------------------------
 # host tools needed to build dist and OTA packages
 
 DISTTOOLS :=  $(HOST_OUT_EXECUTABLES)/minigzip \