##### 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
```

description:
      - If yes, existing listeners will be purged from the ELB to match exactly what is defined by I(listeners) parameter. If the I(listeners) parameter is
        not set then listeners will not be modified
    default: yes
    type: bool
  purge_tags:
    description:
      - If yes, existing tags will be purged from the resource to match exactly what is defined by I(tags) parameter. If the I(tags) parameter is not set then
        tags will not be modified.
    required: false
    default: yes
    type: bool
  subnets:
    description:
      - A list of the IDs of the subnets to attach to the load balancer. You can specify only one subnet per Availability Zone. You must specify subnets from
        at least two Availability Zones. Required if state=present.
    required: false
    type: list
  security_groups:
    description:
      - A list of the names or IDs of the security groups to assign to the load balancer. Required if state=present.
    required: false
    default: []
    type: list
  scheme:
    description:
      - Internet-facing or internal load balancer. An ELB scheme can not be modified after creation.
    required: false
    default: internet-facing
    choices: [ 'internet-facing', 'internal' ]