virsh: Option for overriding disk type in attach-disk
virsh: Option for overriding disk type in attach-disk

Unless --driver tap|file option was given to attach-disk, virsh would
generate <disk type='block'> XML which might be fine for Xen but not for
other hypervisors. This patch introduces a new option --sourcetype which
can be used to explicitly set the type of disk source. The option
accepts either "file" or "block" types.

sshah-solarflare/Libvirt-PCI-passthrough-,nertpinx/libvirt,rmarwaha/libvirt,emaste/libvirt,siboulet/libvirt-openvz,VenkatDatta/libvirt,siboulet/libvirt-openvz,jfehlig/libvirt,iam-TJ/libvirt,datto/libvirt,rmarwaha/libvirt1,libvirt/libvirt,leilihh/libvirt,wiedi/libvirt,soulxu/libvirt-xuhj,elmarco/libvirt,novel/fbsd-libvirt,iam-TJ/libvirt,shugaoye/libvirt,siboulet/libvirt-openvz,olafhering/libvirt,jeckersb/libvirt,VenkatDatta/libvirt,jardasgit/libvirt,emaste/libvirt,novel/fbsd-libvirt,wiedi/libvirt,trainstack/libvirt,elmarco/libvirt,novel/fbsd-libvirt,emaste/libvirt,fabianfreyer/libvirt,usc-isi/libvirt,libvirt/libvirt,danwent/libvirt-ovs,zhlcindy/libvirt-1.1.4-maintain,rmarwaha/libvirt1,shugaoye/libvirt,cbosdo/libvirt,usc-isi/libvirt,iam-TJ/libvirt,rlaager/libvirt,jfehlig/libvirt,rlaager/libvirt,nertpinx/libvirt,leilihh/libvirt,zippy2/libvirt,fabianfreyer/libvirt,emaste/libvirt,jfehlig/libvirt,warewolf/libvirt,iam-TJ/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,rmarwaha/libvirt,zippy2/libvirt,foomango/libvirt,bjzhang/libvirt,andreabolognani/libvirt,novel/fbsd-libvirt,cbosdo/libvirt,rbu/libvirt,datto/libvirt,libvirt/libvirt,eskultety/libvirt,rmarwaha/libvirt,nertpinx/libvirt,olafhering/libvirt,siboulet/libvirt-openvz,cbosdo/libvirt,datto/libvirt,novel/fbsd-libvirt,jeckersb/libvirt,leilihh/libvirt,agx/libvirt,warewolf/libvirt,rbu/libvirt,andreabolognani/libvirt,danwent/libvirt-ovs,agx/libvirt,eskultety/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,eskultety/libvirt,emaste/libvirt,soulxu/libvirt-xuhj,agx/libvirt,VenkatDatta/libvirt,jeckersb/libvirt,kantai/libvirt-vfork,dumbbell/libvirt,dumbbell/libvirt,trainstack/libvirt,rmarwaha/libvirt,warewolf/libvirt,rmarwaha/libvirt1,jardasgit/libvirt,novel/fbsd-libvirt,warewolf/libvirt,nertpinx/libvirt,novel/fbsd-libvirt,leilihh/libvirt,warewolf/libvirt,rbu/libvirt,zhlcindy/libvirt-1.1.4-maintain,olafhering/libvirt,trainstack/libvirt,rbu/libvirt,jeckersb/libvirt,amery/libvirt-vserver,datto/libvirt,foomango/libvirt,rbu/libvirt,danwent/libvirt-ovs,cbosdo/libvirt,danwent/libvirt-ovs,zippy2/libvirt,rmarwaha/libvirt,wiedi/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,shugaoye/libvirt,kantai/libvirt-vfork,emaste/libvirt,leilihh/libvirt,foomango/libvirt,iam-TJ/libvirt,crobinso/libvirt,wiedi/libvirt,trainstack/libvirt,eskultety/libvirt,amery/libvirt-vserver,novel/fbsd-libvirt,libvirt/libvirt,andreabolognani/libvirt,bjzhang/libvirt,trainstack/libvirt,danwent/libvirt-ovs,wiedi/libvirt,bjzhang/libvirt,soulxu/libvirt-xuhj,elmarco/libvirt,bjzhang/libvirt,jeckersb/libvirt,novel/fbsd-libvirt,warewolf/libvirt,zhlcindy/libvirt-1.1.4-maintain,dumbbell/libvirt,jfehlig/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,rmarwaha/libvirt1,wiedi/libvirt,rmarwaha/libvirt1,soulxu/libvirt-xuhj,shugaoye/libvirt,fabianfreyer/libvirt,kantai/libvirt-vfork,amery/libvirt-vserver,taget/libvirt,kantai/libvirt-vfork,usc-isi/libvirt,bjzhang/libvirt,taget/libvirt,trainstack/libvirt,dumbbell/libvirt,trainstack/libvirt,eskultety/libvirt,amery/libvirt-vserver,crobinso/libvirt,elmarco/libvirt,shugaoye/libvirt,jeckersb/libvirt,agx/libvirt,jardasgit/libvirt,soulxu/libvirt-xuhj,rlaager/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,kantai/libvirt-vfork,usc-isi/libvirt,rlaager/libvirt,elmarco/libvirt,usc-isi/libvirt,VenkatDatta/libvirt,iam-TJ/libvirt,zhlcindy/libvirt-1.1.4-maintain,andreabolognani/libvirt,rmarwaha/libvirt,jeckersb/libvirt,jardasgit/libvirt,taget/libvirt,dumbbell/libvirt,iam-TJ/libvirt,siboulet/libvirt-openvz,fabianfreyer/libvirt,leilihh/libvirt,warewolf/libvirt,amery/libvirt-vserver,wiedi/libvirt,taget/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,crobinso/libvirt,rlaager/libvirt,olafhering/libvirt,taget/libvirt,foomango/libvirt,cbosdo/libvirt,nertpinx/libvirt,andreabolognani/libvirt,dumbbell/libvirt,zippy2/libvirt,emaste/libvirt,foomango/libvirt,agx/libvirt,rmarwaha/libvirt1,VenkatDatta/libvirt