[entity] more tweaks for entity attribute cache handling on cw_set/cw_create to fix test regression
* when an attribute is listed in dont-cache-attrs, purge any previous value
* test value is actually modified in EditedEntity.__setitem__ before adding
attribute to dont-cache-attrs
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/entities/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/ext/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/ usr/share/cubicweb/
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/*.py usr/share/pyshared/cubicweb