fixes in sea cfg files

- json_file must be a string, not a list
- rel_path is no longer to be converted to a list

cfg/stick/ill5stick_cfg.py

@@ -13,6 +13,6 @@ Mod('ts',
     'frappy_psi.sea.SeaReadable', '',
     io='sea_stick',
     sea_object='tt',
-    json_file=['ill5.config.json'],
+    json_file='ill5.config.json',
     rel_paths=['ts'],
 )