[gnome-calendar] month-view: fix button release behaviour

[Erick Pérez Castellanos <erickpc src gnome org>]

commit 79ea0817b00372893f8990bfbf90756ca257e5ad
Author: Erick Pérez Castellanos <erick red gmail com>
Date:   Thu Jan 29 09:56:31 2015 -0500

    month-view: fix button release behaviour
    
    When starting from invalid cell button_release vfunc didnt check
    properly the value of the first clicked cell, this led to non-sense
    dates on new-event popover.

 src/gcal-month-view.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gcal-month-view.c b/src/gcal-month-view.c
index db7cf3b..586f257 100644
--- a/src/gcal-month-view.c
+++ b/src/gcal-month-view.c
@@ -1500,7 +1500,7 @@ gcal_month_view_button_release (GtkWidget      *widget,
   priv = gcal_month_view_get_instance_private (GCAL_MONTH_VIEW (widget));
   ppriv = GCAL_SUBSCRIBER_VIEW (widget)->priv;
 
-  if (priv->clicked_cell == -1)
+  if (priv->clicked_cell == -1 || priv->start_mark_cell == -1)
     return FALSE;
 
   days = priv->days_delay + icaltime_days_in_month (priv->date->month, priv->date->year);