[aws/security_group] update mock search and revoke

* update #normalized_permissions to work with GroupId
* fix #describe_security_groups ip-permission.group* filters
[aws/compute] delete_security_group mock fixes

* mock delete failures when instances are present
* fix mock describe_instances by group-id
Merge pull request #2716 from engineyard/firewall-in-use

[aws/security_group] update mock search and revoke