Mute unwanted error message

This CL removes the following line from the top of build logs:
"diff: out/target/product/*/obj/PACKAGING/updater_extensions_intermediates/register.inc.list: No such file or directory"

Change-Id: I79c15a69a0b1b0da0e45620b45a7a0fea5625250
diff --git a/updater/Android.mk b/updater/Android.mk
index dcc6a49..c8f61f4 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -51,7 +51,7 @@
 
 junk := $(shell mkdir -p $(dir $(inc));\
 	        echo $(TARGET_RECOVERY_UPDATER_LIBS) > $(inc).temp;\
-	        diff -q $(inc).temp $(inc).list || cp -f $(inc).temp $(inc).list)
+	        diff -q $(inc).temp $(inc).list 2>/dev/null || cp -f $(inc).temp $(inc).list)
 
 $(inc) : libs := $(TARGET_RECOVERY_UPDATER_LIBS)
 $(inc) : $(inc).list