Removing unused variables from shaft.py and propeller.py

Author: ggurioli

bladex/propeller.py

@@ -75,6 +75,6 @@ def display(self):
         """
         Display the propeller with shaft.
         """
-        display, start_display, add_menu, add_function_to_menu = init_display()
+        display, start_display, _, _ = init_display()
         display.DisplayShape(self.sewed_full_body, update=True)
-        start_display()
+        start_display()

bladex/shaft.py

@@ -55,6 +55,6 @@ def display(self):
         Display the shaft.
         """
         shaft_solid = self.generate_solid()
-        display, start_display, add_menu, add_function_to_menu = init_display()
+        display, start_display, _, _ = init_display()
         display.DisplayShape(shaft_solid, update=True)
-        start_display()
+        start_display()