conf: Fix XML generation for smartcards
conf: Fix XML generation for smartcards

When formatting XML for smartcard device with mode=host, libvirt
generates invalid XML if the device has address info associated:

<smartcard mode='host' <address type='ccid' controller='0' slot='1'/>

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