btrfs-progs: remove a dead break before usage()

The usage() in help.c calls exit(1), so the break behind is nonsense
and should be removed.

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

cmds-property.c

@@ -335,7 +335,6 @@ static void parse_args(int argc, char **argv,
 			break;
 		default:
 			usage(usage_str);
-			break;
 		}
 	}