Add bug number.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86357 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/warn-unused-variables.cpp b/test/SemaCXX/warn-unused-variables.cpp
index 0010489..704fbe2 100644
--- a/test/SemaCXX/warn-unused-variables.cpp
+++ b/test/SemaCXX/warn-unused-variables.cpp
@@ -5,10 +5,10 @@
 	t = 17;
 }
 
+// PR5407
 struct A { A(); };
 struct B { ~B(); };
-
 void f() {
   A a;
   B b;
-}
\ No newline at end of file
+}