silence warning; remove when updating to spyder 5.x.

Index: spyder/app/mainwindow.py
--- spyder/app/mainwindow.py.orig
+++ spyder/app/mainwindow.py
@@ -1327,8 +1327,6 @@ class MainWindow(QMainWindow):
             timer_report_deps = QTimer(self)
             timer_report_deps.setInterval(2000)
             timer_report_deps.setSingleShot(True)
-            timer_report_deps.timeout.connect(
-                self.report_missing_dependencies)
             timer_report_deps.start()
 
         # Raise the menuBar to the top of the main window widget's stack
