[dataimport] Properly escape strings sent to COPY FROM (closes #5278743)
See http://www.postgresql.org/docs/9.1/static/sql-copy.html#AEN64296
for escaping codes.
if not rql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',
ask_confirm=False):
rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',
ask_confirm=False)