[pan2] Fix error found by valgrind: 24 (16 direct, 8 indirect) bytes in 1 blocks are definitely lost in los

[Petr Kovář <pmkovar src gnome org>]

commit c166cc8d6c627de4f839124202df4ddf0b6a96da
Author: Olaf Seibert <rhialto falu nl>
Date:   Mon Mar 21 23:56:16 2016 +0100

    Fix error found by valgrind: 24 (16 direct, 8 indirect) bytes in 1 blocks are definitely lost in loss 
record 3,260 of 11,696
    
       at 0x4C2BBCF: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
       by 0x6D2F578: g_malloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4600.2)
       by 0x6D46762: g_slice_alloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4600.2)
       by 0x524B74D: gtk_tree_path_new (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.28)
       by 0x4A16E5: PanTreeStore::get_path(PanTreeStore::Row const*) const (pan-tree.cc:307)
       by 0x487B41: pan::GroupPane::read_group(pan::StringView const&) (group-pane.cc:848)
       by 0x463938: pan::GUI::root_realized_cb(_GtkWidget*, void*) (gui.cc:194)
       by 0x6A9D014: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4600.2)
       by 0x6AAF060: signal_emit_unlocked_R (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4600.2)
    ...
       by 0x52906B5: gtk_widget_show (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.28)
       by 0x476399: run_pan_in_window (pan.cc:530)
       by 0x476399: main (pan.cc:1108)

 pan/gui/group-pane.cc |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/pan/gui/group-pane.cc b/pan/gui/group-pane.cc
index bb575e6..1c45510 100644
--- a/pan/gui/group-pane.cc
+++ b/pan/gui/group-pane.cc
@@ -849,7 +849,9 @@ GroupPane :: read_group (const StringView& groupname)
       return;
     }
     iter = tree->get_iter (row);
-    read_group(gtk_tree_model_get_path(gtk_tree_view_get_model(view), &iter));
+    GtkTreePath *path = gtk_tree_model_get_path(gtk_tree_view_get_model(view), &iter);
+    read_group (path);
+    gtk_tree_path_free (path);
 }
 
 void