qemu: raise an error when trying to use readonly ide disks
qemu: raise an error when trying to use readonly ide disks

The IDE bus doesn't support readonly disks, so inform the user with an
error message instead of let qemu fail with a more obscure "Device
'ide-hd' could not be initialized" error message.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1112939

Signed-off-by: Giuseppe Scrivano <20002b7b24c75512093a71a58285826d5c504fca@redhat.com>

jfehlig/libvirt,rlaager/libvirt,datto/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,taget/libvirt,eskultety/libvirt,zippy2/libvirt,nertpinx/libvirt,libvirt/libvirt,agx/libvirt,nertpinx/libvirt,libvirt/libvirt,elmarco/libvirt,andreabolognani/libvirt,taget/libvirt,elmarco/libvirt,nertpinx/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,datto/libvirt,jardasgit/libvirt,agx/libvirt,elmarco/libvirt,rlaager/libvirt,andreabolognani/libvirt,elmarco/libvirt,andreabolognani/libvirt,rlaager/libvirt,eskultety/libvirt,jfehlig/libvirt,rlaager/libvirt,jardasgit/libvirt,libvirt/libvirt,zippy2/libvirt,agx/libvirt,zippy2/libvirt,eskultety/libvirt,agx/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,zippy2/libvirt,nertpinx/libvirt,libvirt/libvirt,fabianfreyer/libvirt,crobinso/libvirt,eskultety/libvirt,elmarco/libvirt,jardasgit/libvirt,olafhering/libvirt,fabianfreyer/libvirt,olafhering/libvirt,VenkatDatta/libvirt,taget/libvirt,datto/libvirt,shugaoye/libvirt,andreabolognani/libvirt,eskultety/libvirt,taget/libvirt,shugaoye/libvirt,crobinso/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,shugaoye/libvirt,datto/libvirt,taget/libvirt,VenkatDatta/libvirt,datto/libvirt,crobinso/libvirt,shugaoye/libvirt,rlaager/libvirt,olafhering/libvirt,agx/libvirt,shugaoye/libvirt,crobinso/libvirt,jfehlig/libvirt,olafhering/libvirt