[glom] Avoid unused intermediate value set.

[Murray Cumming <murrayc src gnome org>]

commit 7cdfea3e7c786f0c71971382fce9500d94ff2299
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Nov 3 17:35:16 2015 +0100

    Avoid unused intermediate value set.

 glom/appwindow.cc |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/glom/appwindow.cc b/glom/appwindow.cc
index b4f470f..80c9599 100644
--- a/glom/appwindow.cc
+++ b/glom/appwindow.cc
@@ -456,8 +456,6 @@ void AppWindow::on_menu_help_about()
   {
     //Re-create About box:
     delete m_pAbout;
-    m_pAbout = nullptr;
-
     m_pAbout = new Gtk::AboutDialog;
 
     m_pAbout->set_program_name(m_strAppName);