fix a link issue on windows platform

[carmark]

No description provided.

[Jimmy-Xu]

LGTM

[Jimmy-Xu]

Tested under Win10

>hyper run -d --name some-mysql -e MYSQL_ROOT_PASSWORD=123456 mysql
9f86c8dbfd3cd25eece678ad28135b6c3c17c3a674f4b17a1d5bea3aaed08867

>hyper run -d --name some-wordpress --link some-mysql:mysql -P -d wordpress
d294ec401b733152ac94e5144c62ad51b25ac66b199b1431bbe6820b10663966

>set FIP="209.177.90.208"

>hyper fip attach %FIP%  some-wordpress

>hyper ps | findstr some
d294ec401b73        wordpress                 "docker-entrypoint.sh"   About a minute ago   Up About a minute   0.0.0.0:80->80/tcp       some-wordpress      209.177.90.208
9f86c8dbfd3c        mysql                     "docker-entrypoint.sh"   About a minute ago   Up About a minute                            some-mysql