Fix a couple of memory allocation bugs with namespace processing and XML_UNICODE.
Fix a couple of memory allocation bugs with namespace processing and XML_UNICODE.

libexpat/libexpat,tiran/expat,libexpat/libexpat,libexpat/libexpat,tiran/expat,tiran/expat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,tiran/expat