[rset] New method: ResultSet.one()
This method will return exactly one entity while enforcing its existence and unicity.
The idea is shamelessly borowed from SQLAlchemy Query.one().
Closes #3352314
[jcr: use len(self) instead of len(self.rows)]
#! /bin/sh -e
if [ -x "/etc/init.d/cubicweb-ctl" ]; then
invoke-rc.d cubicweb-ctl restart || true
fi
#DEBHELPER#
exit 0