[gnome-documents] Bump the GTK_MIN_VERSION to 3.15.5

[Pranav Kant <pranavk src gnome org>]

commit c652b1f42b1879e407d3bb277b9aa1457e45b65d
Author: Pranav Kant <pranav913 gmail com>
Date:   Mon Feb 2 19:48:11 2015 +0530

    Bump the GTK_MIN_VERSION to 3.15.5
    
    edge-reached is only available from 3.15.5 onwards.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=743860

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b6e31f6..d7cc536 100644
--- a/configure.ac
+++ b/configure.ac
@@ -52,7 +52,7 @@ AC_SUBST(LIBM)
 EVINCE_MIN_VERSION=3.13.3
 WEBKITGTK_MIN_VERSION=2.6.0
 GLIB_MIN_VERSION=2.39.3
-GTK_MIN_VERSION=3.15.4
+GTK_MIN_VERSION=3.15.5
 GOBJECT_INTROSPECTION_MIN_VERSION=1.31.6
 GDATA_MIN_VERSION=0.13.3
 GOA_MIN_VERSION=3.2.0