[dataimport] Add a ``flush`` method for all stores.
For ``ObjectStore``, ``RQLObjectStore`` and ``NoHookRQLObjectStore``
the method tries to call the ``commit`` method.
For ``SQLGenObjectStore``, the ``flush`` method is basically
unchanged with respect to previous changesets.
/var/log/cubicweb/*.log {
weekly
missingok
rotate 10
compress
delaycompress
notifempty
create 640 root adm
sharedscripts
postrotate
if [ -x /usr/sbin/invoke-rc.d ]; then \
invoke-rc.d cubicweb reload > /dev/null 2>&1; \
else \
/etc/init.d/cubicweb reload > /dev/null 2>&1; \
fi; \
endscript
}