Fix attribute validation with DOM-style input
Fix attribute validation with DOM-style input

pabigot/pyxb,jonfoster/pyxb2,jonfoster/pyxb2,CantemoInternal/pyxb,CantemoInternal/pyxb,jonfoster/pyxb2,CantemoInternal/pyxb,jonfoster/pyxb-upstream-mirror,balanced/PyXB,balanced/PyXB,jonfoster/pyxb-upstream-mirror,pabigot/pyxb,jonfoster/pyxb-upstream-mirror,balanced/PyXB