CU-8699pqzp5 Legacy conversion (#32)

* CU-8699pqzp5: Fix config conversion when old config does not have a value.

* CU-8699pqzp5: Convert en_core_sci_lg to en_core_web_md at model convert time

Author: mart-r

medcat-v2/medcat/utils/legacy/convert_config.py

@@ -71,6 +71,7 @@ def get_val_and_parent_model(old_data: Optional[dict],
                 logger.warning(
                     "Optional path '%s' not found in old config. Ignoring",
                     path)
+                val = None
                 break
             val = val[cname]
     return val, target_model
@@ -166,7 +167,8 @@ def get_config_from_nested_dict(old_data: dict) -> Config:
     # but we now default to regex
     cnf.general.nlp.provider = 'spacy'
     cnf = _make_changes(cnf, old_data)
-    if cnf.general.nlp.modelname in ('spacy_model', 'en_core_sci_md'):
+    if cnf.general.nlp.modelname in ('spacy_model', 'en_core_sci_md',
+                                     'en_core_sci_lg'):
         logger.info("Fixing spacy model. "
                     "Moving from '%s' to 'en_core_web_md'!",
                     cnf.general.nlp.modelname)