PR move of https://github.com/ansible/ansible-modules-core/pull/3588
##### ISSUE TYPE
- Docs Pull Request
##### COMPONENT NAME
ec2_group.py
##### ANSIBLE VERSION
```
ansible 2.0.2.0
config file = /Users/tpai/src/cm-secure/ansible.cfg
configured module search path = Default w/o overrides
```
##### SUMMARY
Make it clear you can specify the created group in the rules list, allowing idempotent use for group<->group networking rules.
This is a really useful feature that isn't obvious enough in the docs.
The default VPC egress rules was being left in the egress rules for
purging in check mode. This ensures that the module returns the correct
change state during check mode.
EC2 Security Group names are unique given a VPC. When a group_name
value is specified in a rule, if the group_name does not exist in the
provided vpc_id it should create the group as per the documentation.
The groups dictionary uses group_names as keys, so it is possible to
find a group in another VPC with the name that is desired. This causes
an error as the security group being acted on, and the security group
referenced in the rule are in two different VPCs.
To prevent this issue, we check to see if vpc_id is defined and if so
check that VPCs match, else we treat the group as new.
* Fixing error exception handling for python. Does not need to be compatible with Python2.4 b/c boto is Python 2.6 and above.
* Fixing error exception handling for python. Does not need to be compatible with Python2.4 b/c boto is Python 2.6 and above.
* Fixing compile time errors IRT error exception handling for Python 3.5.
This does not need to be compatible with Python2.4 b/c Boto is Python 2.6 and above.
Update/fix to Support specifying cidr_ip as a list
Unicode isn't compatible with python2, so we needed some other
solution to this problem. The simplest approach is if the ip item
isn't already a list, simply convert it to one, and we're done.
Thanks to @mspiegle for this suggestion.
Or is "rules_egree" supposed to be a plural? The sentence is difficult to parse.
Maybe the correct fix is to "Purge existing rules on security group that are not found in rules_egress"?
