Fix container_name incorrectly being generated

Checks to see if "container_name" is used correctly in a docker-compose
file conversion and updates the changes respectively in the outputted
artifact files.

For example with container_name set as myfoobarname, the change will
correctly update the "containerNames" portion of the deployment-config
for OpenShift.

"imageChangeParams": {
  "automatic": true,
  "containerNames": [
    "myfoobarname"
  ],
  "from": {
    "kind": "ImageStreamTag",
    "name": "rabbit:3.6.1"
  }
}

Closes https://github.com/kubernetes-incubator/kompose/issues/301

pkg/transformer/openshift/openshift.go

@@ -88,6 +88,12 @@ func (o *OpenShift) initImageStream(name string, service kobject.ServiceConfig)
 // initDeploymentConfig initialize OpenShifts DeploymentConfig object
 func (o *OpenShift) initDeploymentConfig(name string, service kobject.ServiceConfig, replicas int) *deployapi.DeploymentConfig {
 	tag := getImageTag(service.Image)
+	containerName := []string{name}
+
+	// Use ContainerName if it was set
+	if service.ContainerName != "" {
+		containerName = []string{service.ContainerName}
+	}
 
 	dc := &deployapi.DeploymentConfig{
 		TypeMeta: unversioned.TypeMeta{
@@ -126,7 +132,7 @@ func (o *OpenShift) initDeploymentConfig(name string, service kobject.ServiceCon
 					ImageChangeParams: &deployapi.DeploymentTriggerImageChangeParams{
 						//Automatic - if new tag is detected - update image update inside the pod template
 						Automatic:      true,
-						ContainerNames: []string{name},
+						ContainerNames: containerName,
 						From: api.ObjectReference{
 							Name: name + ":" + tag,
 							Kind: "ImageStreamTag",