[facets] should remove groupby from base rqlst. Closes #1796196 as we search for values for a variable, there seems to be no case where we would be interested in groups, though there are clearly some were leaving groups cause errors.

#!/bin/sh -e
if [ "$1" = "purge" ] ; then
        update-rc.d cubicweb remove >/dev/null
fi
 
#DEBHELPER#
 
exit 0