Fix insert statement in database upgrade file 33.

This makes it possible to run the script on an already upgraded
schema.

etc/db/upgrades/upgrade33-v0.5.0-sailline-ancillary-data.sql

@@ -92,7 +92,8 @@ BEGIN
 		sailline, psp.line, 'V' sailline_class, psp.class line_class, pl.incr, pl.ntba, pl.remarks, pl.meta
 	FROM preplot_saillines_points psp
 	INNER JOIN preplot_lines pl ON psp.sailline = pl.line AND pl.class = 'V'
-	ORDER BY sailline;
+	ORDER BY sailline
+	ON CONFLICT DO NOTHING;
 
 	-- We need to recreate the preplot_saillines_points view