cleanup: move clearing of event names to clear_dive_file_data()

Move this to the core so that desktop and mobile don't have
to call this explicitly. Matter of fact, mobile didn't call
this. It is unclear, whether that was even used on mobile,
though.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/divelist.c

@@ -1369,6 +1369,7 @@ void clear_dive_file_data()
 
 	clear_dive(&displayed_dive);
 	clear_device_nodes();
+	clear_events();
 
 	reset_min_datafile_version();
 	clear_git_id();

desktop-widgets/mainwindow.cpp

@@ -660,8 +660,6 @@ void MainWindow::closeCurrentFile()
 		setTitle();
 	disableShortcuts();
 	setFileClean();
-
-	clear_events();
 }
 
 void MainWindow::updateCloudOnlineStatus()