Fixed following SonarQube issues:

- Remove this assignment to the local variable, the value is never used.
  - Rename local variables to match the regular expression
  - Add logic to this except clause or eliminate it and rethrow the exception automatically.
  - Rename fields to match the regular expression
  - Extract this nested conditional expression into an independent statement.
  - Change this default value to "None" and initialize this parameter inside the function/method.
  - Update this function so that its implementation is not identical to __repr__
  - Refactor this method to not always return the same value
  - Reraise this exception to stop the application as the user expects
  - Add missing parameters _w _PY3. This method overrides simplejson.decoder.JSONDecoder.decode.
  - Remove this redundant continue.
  - Remove this unused function declaration
  - Remove this identity check; it will always be False.

web/pgadmin/tools/schema_diff/directory_compare.py

@@ -319,7 +319,7 @@ def are_dictionaries_identical(source_dict, target_dict, ignore_whitespaces,
     return True
 
 
-def directory_diff(source_dict, target_dict, ignore_keys=[], difference={}):
+def directory_diff(source_dict, target_dict, ignore_keys=[], difference=None):
     """
     This function is used to recursively compare two dictionaries and
     return the difference.
@@ -330,6 +330,7 @@ def directory_diff(source_dict, target_dict, ignore_keys=[], difference={}):
     :param difference:
     """
 
+    difference = {} if difference is None else difference
     src_keys = set(source_dict.keys())
     tar_keys = set(target_dict.keys())