Description of problem:
Simliar upstream issue: https://github.com/ansible/ansible/issues/42230

When using the ansible-2.6 to creat Aws scale group, with prerequisites.yml. Installer failed to create ec2 security group due to the unsupported module port "all"

The default port "all" against security group seems not be supported in ansible-2.6 native module ec2_group.

openshift_aws_node_security_groups is defined in the playbook:
roles/openshift_aws/defaults/main.yml
258 openshift_aws_node_security_groups:
259   default:                                
<--snip-->
267     - proto: all
268       from_port: all
269       to_port: all                                   
<--snip-->

and is uesed in roles/openshift_aws/tasks/security_group.yml
  9 - name: create the node group sgs
 10   ec2_group:
 <--snip-->
 16   with_dict: "{{ openshift_aws_node_security_groups }}"

Version-Release number of the following components:
openshift-ansible: git master branch: a7cab9f1218b7

# rpm -qa |grep ansible
ansible-2.6.1-1.el7ae.noarch

# ansible --version
ansible 2.6.1
  config file = /root/openshift-ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, Apr 11 2018, 07:36:10) [GCC 4.8.5 20150623 (Red Hat 4.8.5-28)]


How reproducible:
always

Steps to Reproduce:
1. ansible-playbook -i inventory.yml playbooks/aws/openshift-cluster/prerequisites.yml -e @provisioning_vars.yml
2.
3.

Actual results:
TASK [openshift_aws : create the node group sgs] *************************************************************************************************task path: /root/openshift-ansible/roles/openshift_aws/tasks/security_group.yml:9
Tuesday 17 July 2018  02:45:00 -0400 (0:00:02.903)       0:00:20.540 ********** 
Using module file /usr/lib/python2.7/site-packages/ansible/modules/cloud/amazon/ec2_group.py
<127.0.0.1> ESTABLISH LOCAL CONNECTION FOR USER: root
<127.0.0.1> EXEC /bin/sh -c '/usr/bin/python2 && sleep 0'
The full traceback is:
Traceback (most recent call last):
  File "/tmp/ansible_TPFk1j/ansible_module_ec2_group.py", line 1021, in <module>
    main() 
  File "/tmp/ansible_TPFk1j/ansible_module_ec2_group.py", line 875, in main
    rules = deduplicate_rules_args(rules_expand_sources(rules_expand_ports(module.params['rules'])))
  File "/tmp/ansible_TPFk1j/ansible_module_ec2_group.py", line 607, in rules_expand_ports
    for rule in rule_expand_ports(rule_complex)]
  File "/tmp/ansible_TPFk1j/ansible_module_ec2_group.py", line 584, in rule_expand_ports
    rule['from_port'] = int(rule.get('from_port'))
ValueError: invalid literal for int() with base 10: 'all'

Expected results:
asnsible job is success

Additional info:
Please attach logs from ansible-playbook with the -vvv flag