CP-10204: XenCenter: guest RDP control

This code change is to add changes as bellow:
1. The option "Enable Remote Desktop console scanning"change to"Enable Remote Desktop console scanning (XenServer 6.5 and earlier)"
2. Remove connection between "Automatically switch to the Remote Desktop console when it becomes available" and "Enable Remote Desktop console scanning"
3. Add "Turn on Remote desktop"

One thing need to modify is that "CreedenceorGreater" funtion check should be change.

Signed-off-by: Cheng Zhang <cheng.zhang@citrix.com>