follow yams api change: attributes permissions are now defined for
an 'update' action, no more 'add' / 'delete' which makes no sense in such case.
fix afs.relations_by_section permissions checking of object relation on the way.
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/web usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/shared/data usr/share/cubicweb/cubes/shared
debian/tmp/usr/share/cubicweb/cubes/shared/wdoc usr/share/cubicweb/cubes/shared