Fix packer vsphere-iso builder.

When one's vsphere data center(s) are contained within a data center
folder, vsphere-iso is broken.   There is no way to specificy a "folder"
in the packer template to allow builds to complete.  See
jetbrains-infra/packer-builder-vsphere#285 for
more details.

This change and removal of the folder template key, or using a folder
value that includes "vm/..." allows successful builds.  It is not clear
why vm/ must be in this key and is also in the code.

DCO 1.1 Signed-off-by: David Ohlemacher <[email protected]>

builder/vsphere/driver/folder.go

@@ -21,7 +21,7 @@ func (d *Driver) NewFolder(ref *types.ManagedObjectReference) *Folder {
 }
 
 func (d *Driver) FindFolder(name string) (*Folder, error) {
-	f, err := d.finder.Folder(d.ctx, fmt.Sprintf("/%v/vm/%v", d.datacenter.Name(), name))
+	f, err := d.finder.Folder(d.ctx, fmt.Sprintf("/DataCenters/%v/vm/%v", d.datacenter.Name(), name))
 	if err != nil {
 		return nil, err
 	}