[#1553] Fix migration

backend/server/database/migrations/55_extend_local_host_primary_key.go

@@ -20,6 +20,19 @@ func init() {
 		return err
 	}, func(d migrations.DB) error {
 		_, err := d.Exec(`
+			-- Drop the local host entries where the same host is defined in
+			-- multiple data sources.
+			DELETE FROM local_host lh
+			USING (
+				SELECT host_id, daemon_id
+				FROM local_host
+				GROUP BY host_id, daemon_id
+				HAVING COUNT(*) > 1
+			) d
+			WHERE lh.host_id = d.host_id
+				AND lh.daemon_id = d.daemon_id
+				AND lh.data_source = 'config';
+
 			ALTER TABLE local_host DROP CONSTRAINT local_host_pkey;
 			ALTER TABLE local_host
 				ADD CONSTRAINT local_host_pkey