[gnome-calendar] month-view: only update selection if there's a start date

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

commit ff9c663c8c647a765c0e29e6cb2b50722fee0cdd
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sat Oct 7 11:20:23 2017 -0300

    month-view: only update selection if there's a start date
    
    We can potentially not have an end date set, but there's always
    a start date. If there isn't, it means the user clicked from
    outside of month view, or at an invalid cell, in which cases we
    shouldn't display the quick add popover anyway.

 src/views/gcal-month-view.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/views/gcal-month-view.c b/src/views/gcal-month-view.c
index 8c3027e..8a48989 100644
--- a/src/views/gcal-month-view.c
+++ b/src/views/gcal-month-view.c
@@ -232,7 +232,7 @@ emit_create_event (GcalMonthView *self)
 
   GCAL_ENTRY;
 
-  if (!self->end_mark_cell)
+  if (!self->start_mark_cell || !self->end_mark_cell)
     GCAL_RETURN (FALSE);
 
   should_clear_end = FALSE;
@@ -534,7 +534,7 @@ update_month_cells (GcalMonthView *self)
           selection_start = self->start_mark_cell;
           selection_end = self->end_mark_cell;
 
-          if (selection_start || selection_end)
+          if (selection_start)
             {
               if (!selection_end)
                 selection_end = selection_start;