Add marketplace support to vCenter driver

[OpenNebulaProject]

---

Author Name: Miguel Ángel Álvarez Cabrerizo (Miguel Ángel Álvarez Cabrerizo)
Original Redmine Issue: 5198, https://dev.opennebula.org/issues/5198
Original Date: 2017-06-22

---

So far OpenNebula can import the VMDK files contained in an App imported from the markeplace.

[OpenNebulaProject]

---

Original Redmine Comment
Author Name: Miguel Ángel Álvarez Cabrerizo (Miguel Ángel Álvarez Cabrerizo)
Original Date: 2017-06-22T07:58:45Z

---

The issue is that when you try to attach the VMDK file as a disk, vCenter complains with this message: Error attaching new VM Disk: Error clone virtual disk one/3/0 in datastore nfs. Reason: InvalidArgument: A specified parameter was not correct: fileType.

That error happens beacue the CopyVirtualDisk_Task used to clone a non persistent image, doesn't allow that the file has no extension. The URL used to download a VMDK file from a Marketplace app is: http://marketplace.opennebula.systems//appliance/56e1570d8fb81d0768000002/download/0 and as the file created has no extension the operation fails. It could be solved if the vmdk extension could be added to the downloaded image.

[rsmontero]

Duplicated by #1249