Remove pre-check on ec2:TerminateInstances

[maslick]

Fixing #24

Description of changes: Remove pre-check on ec2:TerminateInstances since this permission is already included in awsutility-cloudformation-commandrun-ExecutionRole - see awsutility-cloudformation-commandrunner.json:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "cloudformation:CreateStack",
                "cloudformation:DeleteStack",
                "cloudformation:DescribeStacks",
                "ec2:AuthorizeSecurityGroupEgress",
                "ec2:AuthorizeSecurityGroupIngress",
                "ec2:CreateSecurityGroup",
                "ec2:CreateTags",
                "ec2:DeleteSecurityGroup",
                "ec2:DescribeInstances",
                "ec2:DescribeSecurityGroups",
                "ec2:DescribeSubnets",
                "ec2:DescribeVpcs",
                "ec2:RevokeSecurityGroupEgress",
                "ec2:RevokeSecurityGroupIngress",
                "ec2:RunInstances",
                "ec2:TerminateInstances",
                "iam:PassRole",
                "iam:SimulatePrincipalPolicy",
                "kms:Decrypt",
                "kms:Encrypt",
                "logs:CreateLogStream",
                "logs:DescribeLogGroups",
                "logs:PutMetricData",
                "ssm:DeleteParameter",
                "ssm:GetParameter",
                "ssm:PutParameter",
                "sts:GetCallerIdentity"
            ],
            "Resource": "*",
            "Effect": "Allow"
        }
    ]
}

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[shantgup]

Added property DisableTerminateInstancesCheck in v2.0.