Fix port residue when instance deletion

A port be implicit-created on ec2 instance creation
if only specify 'SubnetId', so the port id needs to
be stored in instance resource_data so that the port
can be deleted on instance deletion.

Change-Id: I3b685fca26397f8f47d6a732891f06a5360b6487
Closes-bug: #1358581
Merge "Fix port residue when instance deletion"