virt-manager: drop 'xenmigr' scheme from Xen migration URI

For Xen, virt-manager uses a 'xenmigr' URI scheme, which is not
supported by the libvirt libxl driver. Attempting migration
fails with

libvirtError: invalid argument: unable to parse URI: xenmigr://myhost

The old xend-based libvirt driver supports this scheme, but also
supports an empty scheme. It's not clear what the 'xenmigr' scheme
is used for. 'xenmigr' is not referenced by any files in the Xen
code-base, including old branches with xend.

Drop setting scheme to 'xenmigr' when creating the Xen migration URI.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>

virtManager/migrate.py

@@ -344,7 +344,7 @@ class vmmMigrateDialog(vmmGObjectUI):
             return
 
         if self.conn.is_xen():
-            uri = "xenmigr://%s" % address
+            uri = "%s" % address
         else:
             uri = "tcp:%s" % address
         if port: