daemon/config: factor out duplicate xstrdup_tolower

We have two implementations of the same function; let's drop
that to one. We take the name from daemon.c, but the
implementation (which is just slightly more efficient) from
the config code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon.c

@@ -475,14 +475,6 @@ static void make_service_overridable(const char *name, int ena)
 	die("No such service %s", name);
 }
 
-static char *xstrdup_tolower(const char *str)
-{
-	char *p, *dup = xstrdup(str);
-	for (p = dup; *p; p++)
-		*p = tolower(*p);
-	return dup;
-}
-
 static void parse_host_and_port(char *hostport, char **host,
 	char **port)
 {