[gitg] Set margin on first child instead of row itself

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 8f7371789d5bd17425b76730aff849987f6f13f9
Author: Jesse van den Kieboom <jessevdk gmail com>
Date:   Thu Dec 25 12:17:25 2014 +0100

    Set margin on first child instead of row itself

 gitg/history/gitg-history-refs-list.vala |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gitg/history/gitg-history-refs-list.vala b/gitg/history/gitg-history-refs-list.vala
index b52bc46..36e2b21 100644
--- a/gitg/history/gitg-history-refs-list.vala
+++ b/gitg/history/gitg-history-refs-list.vala
@@ -100,12 +100,12 @@ private class RefRow : RefTyped, Gtk.ListBoxRow
 
                if (reference != null)
                {
-                       margin_start += 12;
+                       get_child().margin_start += 12;
                }
 
                if (ref_type == Gitg.RefType.REMOTE)
                {
-                       margin_start += 12;
+                       get_child().margin_start += 12;
                }
 
                d_revealer.notify["child-revealed"].connect(on_child_revealed);