libxl: ignore emulated IDE disks beyond the first 4

libxl: ignore emulated IDE disks beyond the first 4

Qemu supports only 4 emulated IDE disks, when given more (or with higher
indexes), it will fail to start. Since the disks can still be accessible
using PV interface, just ignore emulated path and log a warning, instead
of rejecting the configuration altogether.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>