skip . and .. in accurately in isbridge()

Hi all,

 In commit f88f8 "Skip . and .. in foreach_bridge test", the code skips
 all directories starting with dot.

 But if we create a bridge staring with dot, e.g. `.br0`, then `brctl show`
 cannot show this one.
 `.br0` should not be hidden, because we cannot find it except the command
 `brctl show .br0`.

Signed-off-by: Xiaochen Wang <wangxiaochen0@gmail.com>
1 file changed