[evolution] ECompEditorPageSchedule: Fix some minor issues reported by Coverity Scan

[Milan Crha <mcrha src gnome org>]

commit 8bae14a939b47c97ec30b18fb0f0e421a7a6f108
Author: Milan Crha <mcrha redhat com>
Date:   Fri May 15 16:16:40 2020 +0200

    ECompEditorPageSchedule: Fix some minor issues reported by Coverity Scan
    
    The claim was about not checking return value of e_date_edit_get_date().
    When being in it, added check for the e_date_edit_get_time_of_day()
    value as well and noticed the comp_editor is not unreffed in error
    branches, thus covered also possible memory leak.

 src/calendar/gui/e-comp-editor-page-schedule.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)
---
diff --git a/src/calendar/gui/e-comp-editor-page-schedule.c b/src/calendar/gui/e-comp-editor-page-schedule.c
index 10c728c4b7..36d7bb8384 100644
--- a/src/calendar/gui/e-comp-editor-page-schedule.c
+++ b/src/calendar/gui/e-comp-editor-page-schedule.c
@@ -220,18 +220,31 @@ ecep_schedule_set_time_to_editor (ECompEditorPageSchedule *page_schedule)
        end_tt = e_comp_editor_property_part_datetime_get_value (dtend);
 
        if (!start_tt || !end_tt) {
+               g_clear_object (&comp_editor);
+               g_clear_object (&start_tt);
+               g_clear_object (&end_tt);
+               return;
+       }
+
+       if (!e_date_edit_get_date (E_DATE_EDIT (selector->start_date_edit), &year, &month, &day) ||
+           !e_date_edit_get_time_of_day (E_DATE_EDIT (selector->start_date_edit), &hour, &minute)) {
+               g_clear_object (&comp_editor);
                g_clear_object (&start_tt);
                g_clear_object (&end_tt);
                return;
        }
 
-       e_date_edit_get_date (E_DATE_EDIT (selector->start_date_edit), &year, &month, &day);
-       e_date_edit_get_time_of_day (E_DATE_EDIT (selector->start_date_edit), &hour, &minute);
        i_cal_time_set_date (start_tt, year, month, day);
        i_cal_time_set_time (start_tt, hour, minute, 0);
 
-       e_date_edit_get_date (E_DATE_EDIT (selector->end_date_edit), &year, &month, &day);
-       e_date_edit_get_time_of_day (E_DATE_EDIT (selector->end_date_edit), &hour, &minute);
+       if (!e_date_edit_get_date (E_DATE_EDIT (selector->end_date_edit), &year, &month, &day) ||
+           !e_date_edit_get_time_of_day (E_DATE_EDIT (selector->end_date_edit), &hour, &minute)) {
+               g_clear_object (&comp_editor);
+               g_clear_object (&start_tt);
+               g_clear_object (&end_tt);
+               return;
+       }
+
        i_cal_time_set_date (end_tt, year, month, day);
        i_cal_time_set_time (end_tt, hour, minute, 0);