Fix_ssm_attachment

[herman-wong-cf]

Changes

• Fixed (resource "aws_iam_role_policy_attachment" "ssm_role_policy_attach") count to use 1 or 0 as conditional instead of "length(var.iam_policies)" which would result in multiple attachments of the same policy.
• Changed terraform-aws-securitygroup ref pointer to use a tag version instead of a hash.

[herman-wong-cf]

Add additional conditional of "&& length(var.iam_policies) > 0" to aws_iam_role_policy_attachment.ssm_role_policy_attach "count" as Hunter reports this doesn't work properly on Cisco ASA (no additional IAM policies attached).