GUI: fix npe when selecting ucast in HB config

java.lang.NullPointerException
null
lcmc.gui.dialog.cluster.HbConfig.checkInterface(HbConfig.java:886)
lcmc.gui.dialog.cluster.HbConfig.access$3500(HbConfig.java:89)
lcmc.gui.dialog.cluster.HbConfig$16.check(HbConfig.java:1169)
lcmc.gui.widget.GenericWidget$4$1.run(GenericWidget.java:502)
VMS: fix exceptions during hardware configuration
VMS: fix exception in parallel/serial device

caused by:
null
lcmc.gui.resources.VMSParallelSerialInfo.getRealParametersFromXML(VMSParallelSerialInfo.java:536)
lcmc.gui.resources.VMSVirtualDomainInfo.checkResourceFieldsChanged(VMSVirtualDomainInfo.java:5113)
lcmc.gui.resources.EditableInfo.setApplyButtons(EditableInfo.java:821)
lcmc.gui.resources.VMSHardwareInfo.checkResourceFieldsChanged(VMSHardwareInfo.java:637)
lcmc.gui.resources.VMSHardwareInfo.checkResourceFieldsChanged(VMSHardwareInfo.java:625)
lcmc.gui.resources.VMSSerialInfo.updateParameters(VMSSerialInfo.java:102)
lcmc.gui.resources.VMSVirtualDomainInfo.updateSerialNodes(VMSVirtualDomainInfo.java:1532)
lcmc.gui.resources.VMSVirtualDomainInfo.access$700(VMSVirtualDomainInfo.java:101)
lcmc.gui.resources.VMSVirtualDomainInfo$3.run(VMSVirtualDomainInfo.java:1973)