[gnome-boxes] selectionbar: Add a translation context

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit d12a85ec7edcea99c7612746b9cf5fad8ea081da
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Mon Feb 29 13:11:58 2016 +0000

    selectionbar: Add a translation context
    
    Add context to the button label for the case of "0 boxes selected".
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760391

 src/selectionbar.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/selectionbar.vala b/src/selectionbar.vala
index 2832006..153fdaa 100644
--- a/src/selectionbar.vala
+++ b/src/selectionbar.vala
@@ -149,7 +149,7 @@ private class Boxes.Selectionbar: Gtk.Revealer {
         open_btn.sensitive = items > 0;
         // Translators: This is a button to open box(es) in new window(s)
         if (items == 0)
-            open_btn.label = _("_Open in new window");
+            open_btn.label = C_("0 items selected", "_Open in new window");
         else
             open_btn.label = ngettext ("_Open in new window", "_Open in %d new windows", items).printf 
(items);
     }