fix up some implicit declarations

Change-Id: Ia98bb5bea04a9cb87bf1993687e7f91f46022509
diff --git a/extendedcommands.h b/extendedcommands.h
index 9297f83..a016b84 100644
--- a/extendedcommands.h
+++ b/extendedcommands.h
@@ -44,4 +44,6 @@
 
 void create_fstab();
 
-int has_datadata();
\ No newline at end of file
+int has_datadata();
+
+void handle_failure(int ret);