unable load yangs if there is submodule

Martin Sunal reported problem to load yang files (see attachment) when there is submodule.

I found out that problem is that all of elements (namespaces, augmentations, child nodes... of submodule have namespaces in qname set to null (submodule doesn't have namespace).

Problem could be fixed in package yang-parser-impl class YangParserImpl method addSubmoduleToModule.