[gnome-calendar] month-view: initialize variable

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

commit 1b90c8b413286b3b8f841ee2090b5e0230d3641b
Author: Dominique Leuenberger <dimstar opensuse org>
Date:   Wed Aug 31 19:58:14 2016 +0200

    month-view: initialize variable
    
    Some compilers seem to be over-pessimistic and abort the build with:
    
     gcal-month-view.c: In function 'gcal_month_view_drag_drop':
     gcal-month-view.c:908:32: error: 'timespan' may be used uninitialized in this function 
[-Werror=maybe-uninitialized]
                GDateTime *new_end = g_date_time_add (new_start, timespan);
    
    Even though the usage of the variable is guarded by an equal if as the assignment
    
    https://bugzilla.gnome.org/show_bug.cgi?id=770667

 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 36f23a4..bb8fde2 100644
--- a/src/gcal-month-view.c
+++ b/src/gcal-month-view.c
@@ -865,7 +865,7 @@ gcal_month_view_drag_drop (GtkWidget      *widget,
   gint cell, diff;
   gint start_month, current_month;
   gint start_year, current_year;
-  GTimeSpan timespan;
+  GTimeSpan timespan = 0;
 
   cell = get_dnd_cell (widget, x, y);
   event_widget = gtk_drag_get_source_widget (context);