Pcbnew: fix crash on exit, if a place zone tool is activated.

pcbnew/pcb_edit_frame.cpp

@@ -488,6 +488,10 @@ void PCB_EDIT_FRAME::OnCloseWindow( wxCloseEvent& Event )
         }
     }
 
+    // Be sure no tool is left activated, to avoid crash on exit,
+    // (happens with some tools)
+    GetToolManager()->DeactivateTool();
+
     // On Windows 7 / 32 bits, on OpenGL mode only, Pcbnew crashes
     // when closing this frame if a footprint was selected, and the footprint editor called
     // to edit this footprint, and when closing pcbnew if this footprint is still selected