qemu: process: Simplify access to individual disk when reconnecting
qemu: process: Simplify access to individual disk when reconnecting

Add a helper variable so that we don't have to access the disk via 3
indirections.

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