##### 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
```

if current_listener['Protocol'] != new_listener['Protocol']:
            modified_listener['Protocol'] = new_listener['Protocol']
        
        if current_listener['Protocol'] == 'HTTPS' and new_listener['Protocol'] == 'HTTPS':
            
            if current_listener['SslPolicy'] != new_listener['SslPolicy']:
                modified_listener['SslPolicy'] = new_listener['SslPolicy']
            if current_listener['Certificates'][0]['CertificateArn'] != new_listener['Certificates'][0]['CertificateArn']:
                modified_listener['Certificates'] = []
                modified_listener['Certificates'].append({})
                modified_listener['Certificates'][0]['CertificateArn'] = new_listener['Certificates'][0]['CertificateArn']
        elif current_listener['Protocol'] != 'HTTPS' and new_listener['Protocol'] == 'HTTPS':
            modified_listener['SslPolicy'] = new_listener['SslPolicy']
            modified_listener['Certificates'] = []
            modified_listener['Certificates'].append({})
            modified_listener['Certificates'][0]['CertificateArn'] = new_listener['Certificates'][0]['CertificateArn']
        
        
        if len(current_listener['DefaultActions']) > 1:
            for action in current_listener['DefaultActions']:
                if 'Order' not in action:
                    self.module.fail_json(msg="'Order' key not found in actions. "
                                              "installed version of botocore does not support "
                                              "multiple actions, please upgrade botocore to version "
                                              "1.10.30 or higher")
        
        
        if len(current_listener['DefaultActions']) == len(new_listener['DefaultActions']):