Support docker network's CheckDuplicate at drone exec

[suzuki-shunsuke]

https://godoc.org/github.com/docker/docker/api/types#NetworkCreate
moby/moby#18864

Set Docker network's CheckDuplicate option to prevent name's collisions
at drone exec command.
drone exec executes a local build,
so it is natural to make CheckDuplicate true.

Change of Dependencies should be fixed after the following Pull Request has been merged.

cncd/pipeline#44

[suzuki-shunsuke]

I'm sorry but I misunderstood.
We can't prevent docker network name's collisions by making CheckDuplicate true.

My collegue is suffered from docker network name's collisions at drone exec command.

$ drone exec --local
2018/06/04 15:52:28 Error response from daemon: network drone_default is ambiguous (6 matches found on name)

So I thought we can prevent this error by making CheckDuplicate true, but this is misunderstanding.

I close this issue.