[pkg] Fix extra packages not installable
For instance `pip install -e ".[pyramid]"` should install the pyramid
dependencies. A typo caused all these extra packages to not be found by
pip.
Closes #16121322.
usr/lib/python2*/*-packages/cubicweb/dataimport/
usr/lib/python2*/*-packages/cubicweb/server/
usr/lib/python2*/*-packages/cubicweb/hooks/
usr/lib/python2*/*-packages/cubicweb/sobjects/
usr/lib/python2*/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/