host: Increase container connect timeout

See [this CI log](https://s3.amazonaws.com/flynn-ci-logs/flynn-build-20141207033407-c5108ef7-0ff9479eee0af94fb23a1af11194f6bea0b67c68-2014-12-07-03-42-24.txt) for an example of a job which did not start quickly enough (the job with ID `63414bd61c0149eebddae3e982bbc98f`).

I suspect the slowness is because the scheduler / receiver are overloading particular hosts.