Fix docker usage to use correct port and IP address on local docker

[treydock]

This fixes #43 . Output from local docker run of beaker using this patch:

centos-7 15:07:30$ cat /etc/resolv.conf
  Attempting ssh connection to 127.0.0.1, user: root, opts: {:password=>"root", :port=>"5484", :forward_agent=>false, :auth_methods=>["password", "publickey", "hostbased", "keyboard-interactive"]}

Before this patch my local executions using beaker were trying to connect to the container IP and port 22 both of which won't work.

[treydock]

This is output when only fixing port issue:

centos-7 15:06:32$ cat /etc/resolv.conf
  Attempting ssh connection to 172.17.0.7, user: root, opts: {:password=>"root", :port=>"5484", :forward_agent=>false, :auth_methods=>["password", "publickey", "hostbased", "keyboard-interactive"]}
  Warning: Try 1 -- Host 172.17.0.7 unreachable: Errno::ECONNREFUSED - Connection refused - connect(2) for 172.17.0.7:5484
  Warning: Trying again in 3 seconds

The issue above is the local execution trying to connect to container IP which isn't accessible from the host, should be using loopback address.

This was error with no changes using latest release:

centos-7 15:00:57$ cat /etc/resolv.conf
  Attempting ssh connection to 172.17.0.7, user: root, opts: {:password=>"root", :port=>"22", :forward_agent=>false, :auth_methods=>["password", "publickey", "hostbased", "keyboard-interactive"]}
  Warning: Try 1 -- Host 172.17.0.7 unreachable: Errno::ECONNREFUSED - Connection refused - connect(2) for 172.17.0.7:22
  Warning: Trying again in 3 seconds