Fixup testcase g++.dg/cpp0x/pr31437.C

[Mike Stump]

In fixing a testsuite driver issue, I discovered that some test cases don't 
match the actual output of the compiler.  I'll check in the obvious fixes, I 
believe the below is one such obvious fix.  If people want to argue the 
compiler should instead be changed to match the testcase, let me know.

This is the first of 45 changes...

Index: testsuite/g++.dg/cpp0x/pr31437.C
===================================================================
--- testsuite/g++.dg/cpp0x/pr31437.C    (revision 188225)
+++ testsuite/g++.dg/cpp0x/pr31437.C    (working copy)
@@ -1,5 +1,5 @@
 // { dg-options "-std=gnu++0x" }
-template <typename... T> struct A // { dg-error "candidates|A" }
+template <typename... T> struct A // { dg-message "candidates|A" }
 {
   A(T* p) {  // { dg-error "parameter packs|T" }
    (A<T...>*)(p);