manager: pass ECalObjModType to update and remove

Currently, GcalManager always assumes E_CAL_OBJ_MOD_THIS
when modifying or deleting events. Since we're landing
the groundwork for recurrence management, we can't assume
this anymore.

This patch, then, allows GcalManager:modify_event() and
:remove_event() receive the ECalObjModType instead of
assuming E_CAL_OBJ_MOD_THIS. However, this commit does
not add recurrence support yet, and every call to these
functions are still passing E_CAL_OBJ_MOD_THIS.

https://bugzilla.gnome.org/show_bug.cgi?id=782755

src/views/gcal-month-view.c

@@ -829,7 +829,7 @@ gcal_month_view_drag_drop (GtkWidget      *widget,
           g_clear_pointer (&new_end, g_date_time_unref);
         }
 
-      gcal_manager_update_event (self->manager, event);
+      gcal_manager_update_event (self->manager, event, E_CAL_OBJ_MOD_THIS);
 
       g_clear_pointer (&new_start, g_date_time_unref);
 

src/views/gcal-week-grid.c

@@ -1007,7 +1007,7 @@ gcal_week_grid_drag_drop (GtkWidget      *widget,
   gcal_event_set_date_end (event, new_end);
 
   /* Commit the changes */
-  gcal_manager_update_event (self->manager, event);
+  gcal_manager_update_event (self->manager, event, E_CAL_OBJ_MOD_THIS);
 
   /* Cancel the DnD */
   self->dnd_cell = -1;

src/views/gcal-week-header.c

@@ -1407,7 +1407,7 @@ gcal_week_header_drag_drop (GtkWidget      *widget,
     gcal_event_set_all_day (event, TRUE);
 
   /* Commit the changes */
-  gcal_manager_update_event (self->manager, event);
+  gcal_manager_update_event (self->manager, event, E_CAL_OBJ_MOD_THIS);
 
   /* Cancel the DnD */
   self->dnd_cell = -1;

src/views/gcal-year-view.c

@@ -1512,7 +1512,7 @@ navigator_drag_drop_cb (GcalYearView   *self,
                   g_clear_pointer (&new_end, g_date_time_unref);
                 }
 
-              gcal_manager_update_event (self->manager, event);
+              gcal_manager_update_event (self->manager, event, E_CAL_OBJ_MOD_THIS);
 
               g_clear_pointer (&new_start, g_date_time_unref);
             }