Tighten format string diagnostic and make it a bit clearer (and a bit closer to GCC's).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148579 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/block-printf-attribute-1.c b/test/Sema/block-printf-attribute-1.c
index c19b378..8188ba5 100644
--- a/test/Sema/block-printf-attribute-1.c
+++ b/test/Sema/block-printf-attribute-1.c
@@ -6,6 +6,6 @@
  
   void (^z) (int arg, const char * format, ...) __attribute__ ((__format__ (__printf__, 2, 3))) = ^ __attribute__ ((__format__ (__printf__, 2, 3))) (int arg, const char * format, ...) {};
 
-  z(1, "%s", 1); // expected-warning{{conversion specifies type 'char *' but the argument has type 'int'}}
+  z(1, "%s", 1); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
   z(1, "%s", "HELLO"); // no-warning
 }