[gnome-calendar] source-dialog: fix gtk+ version requirement

[Erick Pérez Castellanos <erickpc src gnome org>]

commit 183cddea3dbc9e413ba966ab914aeeca872fd0e1
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Feb 9 11:48:05 2015 -0200

    source-dialog: fix gtk+ version requirement

 data/ui/source-dialog.ui |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/data/ui/source-dialog.ui b/data/ui/source-dialog.ui
index 91f46c1..27528b0 100644
--- a/data/ui/source-dialog.ui
+++ b/data/ui/source-dialog.ui
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- Generated with glade 3.18.1 -->
 <interface>
-  <requires lib="gtk+" version="3.16"/>
+  <requires lib="gtk+" version="3.15"/>
   <template class="GcalSourceDialog" parent="GtkDialog">
     <property name="can_focus">False</property>
     <property name="type_hint">dialog</property>