[storage/bfss] ensure bfss never remove a cw_edited item (closes #2236287)
When the <old value> == <new value> (not really and update but can happen), the
value was popped but never restored. The cw_edited attribut had wrong content
for a small time lapse.
debian/tmp/usr/bin/cubicweb-ctl usr/bin/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/cwctl.py usr/lib/PY_VERSION/site-packages/cubicweb
debian/cubicweb-ctl.bash_completion etc/bash_completion.d/cubicweb-ctl