##### 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
```

type: str
  state:
    description:
      - Create or destroy the load balancer.
    default: present
    choices: [ 'present', 'absent' ]
    type: str
  tags:
    description:
      - A dictionary of one or more tags to assign to the load balancer.
    required: false
    type: dict
  wait:
    description:
      - Wait for the load balancer to have a state of 'active' before completing. A status check is
        performed every 15 seconds until a successful state is reached. An error is returned after 40 failed checks.
    default: no
    type: bool
    version_added: 2.6
  wait_timeout:
    description:
      - The time in seconds to use in conjunction with I(wait).
    version_added: 2.6
    type: int
  purge_rules:
    description:
      - When set to no, keep the existing load balancer rules in place. Will modify and add, but will not delete.
    default: yes
    type: bool
    version_added: 2.7