[dataimport] massive_store: drop all constraints in __init__ and restore all in finish
This should avoid dependency issues when dropping specific constraints (e.g.
when dropping a primary constraint referenced by a foreign key constraint).
We only do this in master mode, slave mode stores are supposed to work
with an initialized db already.
usr/bin/cubicweb-ctl usr/bin/
usr/lib/python2*/*-packages/cubicweb/cwctl.py
../cubicweb-ctl.bash_completion etc/bash_completion.d/cubicweb-ctl