Try to blindly solve warning about size_t printf format, as I can't reproduce the warning on my machines.

This commit was SVN r17701.

opal/include/opal_stdint.h

@@ -312,12 +312,12 @@ typedef unsigned long long uintptr_t;
 #ifndef PRIsize_t
 # if defined(ACCEPT_C99)
 #   define PRIsize_t "zu"
+# elif SIZEOF_SIZE_T == SIZEOF_INT
+#   define PRIsize_t "u"
 # elif SIZEOF_SIZE_T == SIZEOF_LONG
 #   define PRIsize_t "lu"
 # elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG
 #   define PRIsize_t "llu"
-# elif SIZEOF_SIZE_T == SIZEOF_INT
-#   define PRIsize_t "u"
 # endif
 #endif