[gnote] Fix memory leak if matches box is created but not shown when closing

[Aurimas Černius <aurimasc src gnome org>]

commit 6f25e99b8d0c202adde20a40492698e2b905a6aa
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Tue Jan 5 16:19:42 2021 +0200

    Fix memory leak if matches box is created but not shown when closing

 src/searchnoteswidget.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/src/searchnoteswidget.cpp b/src/searchnoteswidget.cpp
index c6477b74..bfad5f37 100644
--- a/src/searchnoteswidget.cpp
+++ b/src/searchnoteswidget.cpp
@@ -118,6 +118,9 @@ SearchNotesWidget::~SearchNotesWidget()
   if(m_notebook_list_context_menu) {
     delete m_notebook_list_context_menu;
   }
+  if(m_no_matches_box) {
+    delete m_no_matches_box;
+  }
 }
 
 Glib::ustring SearchNotesWidget::get_name() const
@@ -1034,7 +1037,7 @@ void SearchNotesWidget::no_matches_found_action()
     no_matches_found->set_hexpand(true);
     no_matches_found->set_vexpand(true);
     no_matches_found->show_all();
-    m_no_matches_box = manage(new Gtk::Grid);
+    m_no_matches_box = new Gtk::Grid;
     m_no_matches_box->attach(*no_matches_found, 0, 0, 1, 1);
     m_no_matches_box->show();
   }