glib: Change API for repeating an in-thread scheduled task

Previously, in glib.schedule(), when in_thread is set to True, it is expected
that the task method return whether it wants to be repeated (True) or
not (False). However, this was not documented and different from the behavior of
the separate-thread task (passed as argument repeat=). To simply and improve
consistency, use the repeat= argument instead of return value from the method.

This fixes issue with daily diagnostics not running for the second time.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/glib.py

@@ -65,7 +65,8 @@ def schedule(interval, method, data=None, in_thread=True, repeat=True,
     def _run_bare_or_thread(_user_data):
         """Run the target method in thread or directly (if async)."""
         if not in_thread:
-            return _runner()
+            _runner()
+            return repeat
 
         thread = threading.Thread(target=_runner)
         thread.start()