fix npe in DRBD volume menu

caused by:
lcmc.gui.resources.drbd.VolumeMenu$1 cannot be cast to
javax.swing.Action
lcmc.gui.resources.drbd.ResourceMenu$1.updateAndWait(ResourceMenu.java:41)
lcmc.gui.resources.Info$9.run(Info.java:660)
junit tests for menus
fix debug output