Correctly index SecurityGroupId parameter

run_instances does not follow the spec when it comes to formatting the input parameters.

In particular, if we pass an array as 'SecurityGroupId' inside the 'NetworkInterfaces' array, it does not get parameterized as "NetworkInterface.%d.SecurityGroupId.%d'.


Spec: http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-RunInstances.html