[gnome-calendar/gnome-3-34] manager: Only remove connected calendars

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 8cb818f4d94533846ac0567738da93f4658dd053
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Oct 9 13:02:35 2019 -0300

    manager: Only remove connected calendars
    
    The "source-removed" signal can pass any kind of source,
    including source collections that even have the calendar
    extension, but are not connected.

 src/core/gcal-manager.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/src/core/gcal-manager.c b/src/core/gcal-manager.c
index c5ba0432..afbdacbf 100644
--- a/src/core/gcal-manager.c
+++ b/src/core/gcal-manager.c
@@ -165,11 +165,15 @@ remove_source (GcalManager  *self,
   g_return_if_fail (GCAL_IS_MANAGER (self));
   g_return_if_fail (E_IS_SOURCE (source));
 
+  calendar = g_hash_table_lookup (self->clients, source);
+
+  if (!calendar)
+    return;
+
   GCAL_TRACE_MSG ("Removing calendar %s (%s)",
                   e_source_get_display_name (source),
                   e_source_get_uid (source));
 
-  calendar = g_hash_table_lookup (self->clients, source);
   g_object_ref (calendar);
 
   e_cal_data_model_remove_client (self->e_data_model,