bootctl: fix -q option

Follow up to 14e6e44

(cherry picked from commit 4697ee9)

src/boot/bootctl.c

@@ -260,7 +260,7 @@ static int parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "hpxR", options, NULL)) >= 0)
+        while ((c = getopt_long(argc, argv, "hpxRq", options, NULL)) >= 0)
                 switch (c) {
 
                 case 'h':