libxl: add support for rbd qdisk
libxl: add support for rbd qdisk

xl/libxl already supports qemu's network-based block backends
such as nbd and rbd. libvirt has supported configuring such
<disk>s for long time too. This patch adds support for rbd
disks in the libxl driver by generating a rbd device URL from
the virDomainDiskDef object. The URL is passed to libxl via the
pdev_path field of libxl_device_disk struct. libxl then passes
the URL to qemu for cosumption by the rbd backend.

Signed-off-by: Jim Fehlig <39929b5b86d72d51fceac59b52303e3fe8a3083e@suse.com>

datto/libvirt,libvirt/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,libvirt/libvirt,andreabolognani/libvirt,eskultety/libvirt,datto/libvirt,eskultety/libvirt,jardasgit/libvirt,andreabolognani/libvirt,jfehlig/libvirt,jfehlig/libvirt,olafhering/libvirt,zippy2/libvirt,fabianfreyer/libvirt,zippy2/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,eskultety/libvirt,jardasgit/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,taget/libvirt,jardasgit/libvirt,olafhering/libvirt,andreabolognani/libvirt,libvirt/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,taget/libvirt,nertpinx/libvirt,olafhering/libvirt,crobinso/libvirt,datto/libvirt,taget/libvirt,jfehlig/libvirt,datto/libvirt,crobinso/libvirt,eskultety/libvirt,nertpinx/libvirt,libvirt/libvirt,olafhering/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,zippy2/libvirt,taget/libvirt,zippy2/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,taget/libvirt,datto/libvirt,nertpinx/libvirt,crobinso/libvirt,crobinso/libvirt,andreabolognani/libvirt,jardasgit/libvirt,eskultety/libvirt,nertpinx/libvirt