In case of two or more iso_urls checks for downloaded files prior to downloading them.
Speedups case when some iso already downloaded and another url prepended to iso_urls list.
This driver talks directly to ESX over ssh, using vim-cmd, esxcli and sh;
no vCenter or VIM api required.
Remote* config properties added to support a remote driver
RemoteDriver interface extends Driver:
* SSHAddress - esx flavor uses esxcli to find the VM's ip address
* Download - esx flavor downloads iso files to a vmfs datastore
Driver can optionally implement the following interfaces:
* VNCAddressFinder - esx flavor needs to check remote ports
* OutputDir - esx driver needs a local and remote OutputDir
* Inventory - esx driver needs to register/unregister VMs
* HostIPFinder - esx flavor needs an address on the same network as esx itself