Simplify some more call signature things

jedi/api/__init__.py

@@ -345,12 +345,11 @@ class Script(object):
         )
         debug.speed('func_call followed')
 
-        return [classes.CallSignature(signature._context, signature,
+        return [classes.CallSignature(self._evaluator, signature,
                                       call_signature_details.bracket_leaf.start_pos,
                                       call_signature_details.call_index,
                                       call_signature_details.keyword_name_str)
-                for definition in definitions
-                for signature in definition.get_signatures()]
+                for signature in definitions.get_signatures()]
 
     def _analysis(self):
         self._evaluator.is_analysis = True