ansible/ansible-modules-core — pull request #318 by erydo (2014-11-13 23:11:50+00:00)
Title: Allow empty EC2 Security Group rules.

Previously, there was no way to force "no egress rules" on a security group short of specifying a phony group. (e.g. "only access localhost"). This was counter to intuition about what `purge_egress_rules` etc. did.

This allows you to set up a rule like:
```yaml
- name: Set up security group for package clients
local_action:
module: ec2_group
name: 'package-client'
description: Can retrieve packages from package servers
vpc_id: '{{vpc_res.vpc.id}}'
region: '{{vpc_res.vpc.region}}'
rules: []
rules_egress:
- proto: tcp
from_port: 80
to_port: 80
group_name: 'package-server'
group_desc: Build server and apt repository security group
- proto: tcp
from_port: 443
to_port: 443
group_name: 'package-server'
```

Which will create a security group with *only* the rules specified.