updating check for container_info networkings port

[nandeshguru]

PR for issue #37 load_with_context': undefined method `each' for nil:NilClass (NoMethodError) exception in cis-docker-benchmark-master/controls/container_runtime.rb:194

[atomic111]

@coolguru Thank you for your PR. i think it should be like if !container_info... because i test there if the object empty. May be i am wrong?

[atomic111]

@coolguru Sorry, to early for me today. you are right.

inspec> docker.object('40c6ad921df7428069626637cc2d43b8d2d9404aa440e00fd0eb37d11406e14c')['NetworkSettings']['Ports']
=> {}
inspec> docker.object('40c6ad921df7428069626637cc2d43b8d2d9404aa440e00fd0eb37d11406e14c')['NetworkSettings']['Ports'].nil?
=> false

[atomic111]

@coolguru thanks for the BugFix. great!!!