Fix stack acceptance tests (#395)

Author: florindragos

spec/spec_helper_acceptance.rb

@@ -142,7 +142,6 @@ def retry_on_error_matching(max_retry_count = 3, retry_wait_interval_secs = 5, e
 services:
   compose_test:
     image: hello-world:nanoserver-sac2016
-    command: cmd.exe /C "ping 8.8.8.8 -t"
       EOS
       if fact_on(host, 'osfamily') == 'windows'
         create_remote_file(host, '/tmp/docker-compose-v3.yml', docker_compose_content_v3_windows)