Fix uninitialized variable.

(cherry picked from commit 1e1aedbe30)

cvpcb/cvpcb_mainframe.cpp

@@ -62,6 +62,7 @@
 CVPCB_MAINFRAME::CVPCB_MAINFRAME( KIWAY* aKiway, wxWindow* aParent ) :
         KIWAY_PLAYER( aKiway, aParent, FRAME_CVPCB, _( "Assign Footprints" ), wxDefaultPosition,
                       wxDefaultSize, KICAD_DEFAULT_DRAWFRAME_STYLE, CVPCB_MAINFRAME_NAME ),
+        m_footprintListPendingUpdate( false ),
         m_viewerPendingUpdate( false )
 {
     m_symbolsListBox      = nullptr;