##### SUMMARY
When using the `host-header` condition for a load balancer rule if there are multiple values for the host header ansible fails to apply the changes with broken json output.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
elbv2

##### ANSIBLE VERSION
```
ansible 2.10.0.dev0
  config file = None
  configured module search path = [u'/home/mjmayer/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /home/mjmayer/repos/ansible/lib/ansible
  executable location = /home/mjmayer/repos/ansible/bin/ansible
  python version = 2.7.15+ (default, Oct  7 2019, 17:39:04) [GCC 7.4.0]

```

##### CONFIGURATION
```
```

##### OS / ENVIRONMENT
Mint 19.2 / Ubuntu 18.04

##### STEPS TO REPRODUCE

```yaml
  - name: add a rule that uses the host header condition to the listener
    elb_application_lb:
      name: "{{ alb_name }}"
      subnets: "{{ alb_subnets }}"
      security_groups: "{{ sec_group.group_id }}"
      state: present
      purge_rules: no
      listeners:
        - Protocol: HTTP
          Port: 80
          DefaultActions:
            - Type: forward
              TargetGroupName: "{{ tg_name }}"
          Rules:
            - Conditions:
                - Field: host-header
                  Values:
                    - 'local.mydomain.com'
              Priority: '3'
              Actions:
                - TargetGroupName: "{{ tg_name }}"
                  Type: forward
      <<: *aws_connection_info
    register: alb

  - assert:
      that:
        - alb.changed
        - alb.listeners[0].rules|length == 4

  - name: test replacing the rule that uses the host header condition with multiple host header conditions
    elb_application_lb:
      name: "{{ alb_name }}"
      subnets: "{{ alb_subnets }}"
      security_groups: "{{ sec_group.group_id }}"
      purge_rules: no
      state: present
      listeners:
        - Protocol: HTTP
          Port: 80
          DefaultActions:
            - Type: forward
              TargetGroupName: "{{ tg_name }}"
          Rules:
            - Conditions:
                - Field: host-header
                  Values:
                    - 'local.mydomain.com'
                    - 'alternate.mydomain.com'
              Priority: '3'
              Actions:
                - TargetGroupName: "{{ tg_name }}"
                  Type: forward
      <<: *aws_connection_info
    register: alb
```
##### EXPECTED RESULTS
The second application of `elb_application_lb` should succeed and add the second host-header.


##### ACTUAL RESULTS
Ansible prints invalid json to the screen with the following error.
```paste below
Module invocation had junk after the JSON data
```

def __init__(self, connection, connection_ec2, module):
        """
        :param connection: boto3 connection
        :param module: Ansible module
        """
        super(ApplicationLoadBalancer, self).__init__(connection, module)
        self.connection_ec2 = connection_ec2
        
        self.type = 'application'
        if module.params.get('security_groups') is not None:
            try:
                self.security_groups = AWSRetry.jittered_backoff()(
                    get_ec2_security_group_ids_from_names
                )(module.params.get('security_groups'), self.connection_ec2, boto3=True)
            except ValueError as e:
                self.module.fail_json(msg=str(e), exception=traceback.format_exc())
            except (BotoCoreError, ClientError) as e:
                self.module.fail_json_aws(e)
        else:
            self.security_groups = module.params.get('security_groups')
        self.access_logs_enabled = module.params.get("access_logs_enabled")
        self.access_logs_s3_bucket = module.params.get("access_logs_s3_bucket")
        self.access_logs_s3_prefix = module.params.get("access_logs_s3_prefix")
        self.idle_timeout = module.params.get("idle_timeout")
        self.http2 = module.params.get("http2")
        if self.elb is not None and self.elb['Type'] != 'application':
            self.module.fail_json(msg="The load balancer type you are trying to manage is not application. Try elb_network_lb module instead.")
    def create_elb(self):