remove unused byte from user agent buffer

snprintf prints at most n bytes including the terminating '\0'.  The
extra reserved byte was never being used.

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

src/pacman/pacman.c

@@ -269,7 +269,7 @@ static void localize(void)
  */
 static void setuseragent(void)
 {
-	char agent[101];
+	char agent[100];
 	struct utsname un;
 	int len;