Bug#641593: add project category crash resurfaced

[Guo Yixuan]

Hi,

This is about the bug #641593 [1], I compiled boincmgr with 
"--enable-debug --enable-wx-debug". Here is the backtrace it got when 
reproducing the crash.

[1] http://bugs.debian.org/641593

Regards,

Guo Yixuan

ASSERT INFO:
../src/gtk/listbox.cpp(674): assert "IsValid(n)" failed in 
DoGetItemClientData(): Invalid index passed to GetItemClientData

BACKTRACE:
[1] wxListBox::DoGetItemClientData(unsigned int) cons)
[2] wxItemContainer::GetClientData(unsigned int) cons)
[3] wxControlWithItems::GetClientData(unsigned int) cons) 
/usr/include/wx-2.8/wx/ctrlsub.h:185
[4] CProjectInfoPage::OnProjectSelected(wxCommandEvent&) 
/home/gyx/pkg/boinc/boinc-7.0.25+dfsg/clientgui/ProjectInfoPage.cpp:479
[5] wxAppConsole::HandleEvent(wxEvtHandler*, void 
(wxEvtHandler::*)(wxEvent&), wxEvent&) cons)
[6] wxEvtHandler::ProcessEventIfMatches(wxEventTableEntryBase const&, 
wxEvtHandler*, wxEvent&)
[7] wxEventHashTable::HandleEvent(wxEvent&, wxEvtHandler*)
[8] wxEvtHandler::ProcessEvent(wxEvent&)
[9] wxWindowBase::TryParent(wxEvent&)
[10] wxEvtHandler::ProcessEvent(wxEvent&)
[11] g_cclosure_marshal_VOID__VOIDv()
[12] g_signal_emit_valist()
[13] g_signal_emit_by_name()
[14] g_cclosure_marshal_VOID__BOXED()
[15] g_closure_invoke()
[16] g_signal_emit_valist()
[17] g_signal_emit()
[18] gtk_tree_model_row_deleted()
[19] gtk_list_store_remove()
[20] gtk_list_store_clear()
[21] wxListBox::Clear()
[22] CProjectInfoPage::OnProjectCategorySelected(wxCommandEvent&) 
/home/gyx/pkg/boinc/boinc-7.0.25+dfsg/clientgui/ProjectInfoPage.cpp:449
[23] wxAppConsole::HandleEvent(wxEvtHandler*, void 
(wxEvtHandler::*)(wxEvent&), wxEvent&) cons)
[24] wxEvtHandler::ProcessEventIfMatches(wxEventTableEntryBase const&, 
wxEvtHandler*, wxEvent&)
[25] wxEventHashTable::HandleEvent(wxEvent&, wxEvtHandler*)
[26] wxEvtHandler::ProcessEvent(wxEvent&)
[27] wxWindowBase::TryParent(wxEvent&)
[28] wxEvtHandler::ProcessEvent(wxEvent&)
[29] g_cclosure_marshal_VOID__VOID()
[30] g_closure_invoke()
[31] g_signal_emit_valist()
[32] g_signal_emit()
[33] gtk_combo_box_set_active_iter()
[34] g_cclosure_marshal_VOID__VOID()
[35] g_closure_invoke()
[36] g_signal_emit_valist()
[37] g_signal_emit()
[38] gtk_widget_activate()
[39] gtk_menu_shell_activate_item()
[40] g_closure_invoke()
[41] g_signal_emit_valist()
[42] g_signal_emit()
[43] gtk_propagate_event()
[44] gtk_main_do_event()
[45] g_main_context_dispatch()
[46] g_main_loop_run()
[47] gtk_main()
[48] wxEventLoop::Run()
[49] wxDialog::ShowModal()
[50] wxWizardEx::RunWizard(wxWizardPageEx*) 
/home/gyx/pkg/boinc/boinc-7.0.25+dfsg/clientgui/wizardex.cpp:595
[51] CWizardAttach::Run(wxString&, wxString&, wxString&, bool) 
/home/gyx/pkg/boinc/boinc-7.0.25+dfsg/clientgui/WizardAttach.cpp:382