[test rql completion] dont limit number of completion, else we've impredicable results. Also should tell rql.parse to not print error on stdout This repairs test introduced by dcd9bc1d1bca which closes #2439846

bgcolor = '#000000'
stylesheets = ['%s/cubicweb.css' % datadir_url]
logo = '%s/logo.png' % datadir_url
lazy = lazystr('%(bgcolor)s')