builtin/config.c: compilation fix

Do not feed a random string as the first parameter to die(); use "%s"
as the format string instead.

Do the same for test-urlmatch-normalization.c while saving a single
pointer variable by turning a "const char *" constant string into
"const char []", which is sufficient to squelch compilation warning
(the compiler can see usage[] given to die() is a constant and will
never have conversion specifiers that cause trouble).  But for a
good measure, give them the same "%s" treatment as well.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/config.c

@@ -404,7 +404,7 @@ static int get_urlmatch(const char *var, const char *url)
 	config.cb = &values;
 
 	if (!url_normalize(url, &config.url))
-		die(config.url.err);
+		die("%s", config.url.err);
 
 	config.section = dup_downcase(var);
 	section_tail = strchr(config.section, '.');