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/sch_cfg.py

@@ -21,7 +21,7 @@ Mod('warmup',
 Mod('ts',
     'secop_psi.sea.SeaReadable', '',
     sea_object='tt',
-    json_file=['ori4.config.json'],
+    json_file='ori4.config.json',
     rel_paths=['ts'],
     io='sea_stick',
 )