Description of problem:
Could not find the requested service container-engine while configuring "openshift_docker_use_system_container=false" in inventory file
fatal: [ec2-54-85-194-178.compute-1.amazonaws.com]: FAILED! => {"attempts": 3, "changed": false, "failed": true, "msg": "Could not find the requested service container-engine: host"}

When "openshift_docker_use_system_container=false", installer should restart "docker" service, but not "container-engine", obviously, installer set openshift.docker.service_name to "container-engine" incorrectly.

Version-Release number of the following components:
openshift-ansible-3.7.0-0.128.0.git.0.89dcad2.el7.noarch.rpm

How reproducible:
always

Steps to Reproduce:
1.cat inventory_file
<--snip-->
openshift_docker_use_system_container=false
<--snip-->


Actual results:
RUNNING HANDLER [docker : restart docker] **************************************
Thursday 28 September 2017  06:38:03 +0000 (0:00:00.034)       0:00:42.890 **** 
FAILED - RETRYING: restart docker (3 retries left).
FAILED - RETRYING: restart docker (2 retries left).
FAILED - RETRYING: restart docker (1 retries left).
fatal: [ec2-54-85-194-178.compute-1.amazonaws.com]: FAILED! => {"attempts": 3, "changed": false, "failed": true, "msg": "Could not find the requested service container-engine: host"}

Expected results:

Additional info:
From the docker facts log, looks like openshift_facts didn't get a valid bool value from `openshift_docker_use_system_container=false`
$ grep -nir "use_system_container" roles/openshift_facts/library/openshift_facts.py 

1683:        if facts['docker']['use_system_container']:


TASK [openshift_docker_facts : Set docker facts] *******************************
docker": {"additional_registries": ["registry.xxx.openshift.com", "registry.access.redhat.com"], "api_version": 1.24, "blocked_registries": ["registry.hacker.com"], "disable_push_dockerhub": false, "gte_1_10": true, "hosted_registry_insecure": false, "hosted_registry_network": "172.30.0.0/16", "insecure_registries": ["xxxxxxxm:8888", "virt-openshift-05.lab.eng.nay.redhat.com:5000", "virt-openshift-05.lab.eng.nay.redhat.com:5001", "registry.ops.openshift.com", "asb-registry.usersys.redhat.com:5000"], "options": "--log-driver=journald", "service_name": "container-engine", "use_crio": false, "use_system_container": "false", "version": "1.12.6"}