Assume QEMU_CAPS_DEVICE in qemuBuildDiskDriveCommandLine
Assume QEMU_CAPS_DEVICE in qemuBuildDiskDriveCommandLine

We no longer need to handle -usbdevice and the withDeviceArg
logic becomes clearer.

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