[vala] Mark the icon property of GtkModelButton as nullable.

[Arnaud Bonatti <arnaudb src gnome org>]

commit 55127b74a71a3e5d84cb034fd12b5463f2f592da
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Aug 31 05:22:53 2016 +0200

    Mark the icon property of GtkModelButton as nullable.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=770180

 vapi/gtk+-3.0.vapi                       |    2 +-
 vapi/packages/gtk+-3.0/gtk+-3.0.metadata |    1 +
 2 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/vapi/gtk+-3.0.vapi b/vapi/gtk+-3.0.vapi
index 6b720ac..dde36ba 100644
--- a/vapi/gtk+-3.0.vapi
+++ b/vapi/gtk+-3.0.vapi
@@ -3523,7 +3523,7 @@ namespace Gtk {
                [NoAccessorMethod]
                public bool centered { get; set; }
                [NoAccessorMethod]
-               public GLib.Icon icon { owned get; set; }
+               public GLib.Icon? icon { owned get; set; }
                [NoAccessorMethod]
                public bool iconic { get; set; }
                [NoAccessorMethod]
diff --git a/vapi/packages/gtk+-3.0/gtk+-3.0.metadata b/vapi/packages/gtk+-3.0/gtk+-3.0.metadata
index 99cbfcf..cb50d92 100644
--- a/vapi/packages/gtk+-3.0/gtk+-3.0.metadata
+++ b/vapi/packages/gtk+-3.0/gtk+-3.0.metadata
@@ -855,6 +855,7 @@ gtk_misc_get_alignment.xalign is_out="1"
 gtk_misc_get_alignment.yalign is_out="1"
 gtk_misc_get_padding.xpad is_out="1"
 gtk_misc_get_padding.ypad is_out="1"
+GtkModelButton:icon nullable="1"
 GtkModuleInitFunc.argc hidden="1"
 GtkModuleInitFunc.argv is_array="1" nullable="1" transfer_ownership="1" array_length_cname="argc" 
array_length_pos="0.5"
 gtk_mount_operation_is_showing hidden="1"