[evolution] Fix a crash when deleting a meeting without DTEND

[Milan Crha <mcrha src gnome org>]

commit 47b8b332ca0e8b695ca9333591f36933eb8eda53
Author: Milan Crha <mcrha redhat com>
Date:   Tue Dec 13 14:32:56 2016 +0100

    Fix a crash when deleting a meeting without DTEND

 src/calendar/gui/e-cal-dialogs.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)
---
diff --git a/src/calendar/gui/e-cal-dialogs.c b/src/calendar/gui/e-cal-dialogs.c
index 9dc4084..87d85a3 100644
--- a/src/calendar/gui/e-cal-dialogs.c
+++ b/src/calendar/gui/e-cal-dialogs.c
@@ -44,9 +44,16 @@ is_past_event (ECalComponent *comp)
        ECalComponentDateTime end_date;
        gboolean res;
 
-       if (!comp) return TRUE;
+       if (!comp)
+               return TRUE;
+
+       end_date.value = NULL;
 
        e_cal_component_get_dtend (comp, &end_date);
+
+       if (!end_date.value)
+               return FALSE;
+
        res = icaltime_compare_date_only (
                *end_date.value,
                icaltime_current_time_with_zone (