Remove code for old pylspclient

Author: tom-tan

cwl_language_server/callbacks.py

@@ -21,7 +21,6 @@ def initialized(params): # InitializedParams -> None
 
 def completion(params): # CompletionParams -> CompletionList
     # print('Params: ', params, file=sys.stderr)
-    params = params['params']
     ctx = params.get('context', {})
     line = params['position']['line']
     col = params['position']['character']