FP2-1752: add SU for apps to userdebug builds.

Do not build standard su binary when FP2_USE_APPOPS_SU is set.

FPIIM-648

Change-Id: Iec4883b4de183161a1e147ec1cf2d233274255e6
diff --git a/su/Android.mk b/su/Android.mk
index 297e0a3..4130310 100644
--- a/su/Android.mk
+++ b/su/Android.mk
@@ -1,3 +1,4 @@
+ifneq ($(FP2_USE_APPOPS_SU),true)
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
@@ -11,3 +12,4 @@
 LOCAL_MODULE_TAGS := debug
 
 include $(BUILD_EXECUTABLE)
+endif