Only include uncrypt if not in system/core

Some android trees have uncrypt in system/core (cm-11.0). This breaks
building recovery since two modules of the same name conflict. Only
include the local copy of uncrypt if it doesn't already exist in
system/core.

Change-Id: Ie2d7cdedf0d4c9ad148c43b317d1f22d1e50e1f7

Android.mk

@@ -479,10 +479,13 @@ include $(LOCAL_PATH)/minui/Android.mk \
     $(LOCAL_PATH)/tests/Android.mk \
     $(LOCAL_PATH)/tools/Android.mk \
     $(LOCAL_PATH)/edify/Android.mk \
-    $(LOCAL_PATH)/uncrypt/Android.mk \
     $(LOCAL_PATH)/updater/Android.mk \
     $(LOCAL_PATH)/applypatch/Android.mk
 
+ifeq ($(wildcard system/core/uncrypt/Android.mk),)
+    include $(commands_recovery_local_path)/uncrypt/Android.mk
+endif
+
 #includes for TWRP
 include $(commands_recovery_local_path)/injecttwrp/Android.mk \
     $(commands_recovery_local_path)/htcdumlock/Android.mk \