xl: Ensure that the params key gets set to "" when starting a VM with empty CDROM drive
xl: Ensure that the params key gets set to "" when starting a VM with empty CDROM drive

Signed-off-by: Rob Hoes <8783b3376fb07d39edffc8d7da68a6de3874a7e6@citrix.com>

koushikcgit/xenopsd,euanh/xenopsd,koushikcgit/xenopsd,cheng--zhang/xenopsd,koushikcgit/xenopsd,thomassa/xenopsd,djs55/xenopsd,thomassa/xenopsd,thomassa/xenopsd,djs55/xenopsd,cheng--zhang/xenopsd,johnelse/xenopsd,euanh/xenopsd,djs55/xenopsd,cheng--zhang/xenopsd,johnelse/xenopsd,johnelse/xenopsd,euanh/xenopsd