test which verifies authorizing rules within a VPC is broken see issue #108
We're getting back the correct group from get_security_group_from_id,
but hitting another issue with the source_group_name also using an id
rather than a name
VPC support for adding rules improving
fix for VPC revoking of rules related to groups
removed unnecessary itertools chain.
added success test case around authorize & revoke
Merge pull request #109 from StartTheShift/fix_vpc_grant_permission_issue

Fix vpc grant permission to groups issue