pvdc_migrate_vms double escaping vc_name, causes lookup failure

[jlarmstrong]

Reference: https://github.com/vmware/pyvcloud/blob/16390969c84c1b82359934d48b8aaa1a98be2113/pyvcloud/vcd/platform.py#L768

The use of urllib.parse.quote(vc_name) causes "_" and other special characters to be double escaped in the request.