Repairing XMLStreamWriter tries to bind xml namespace URI

[cowtowncoder]

(note: result of FasterXML/jackson-dataformat-xml#395)

Looks like Woodstox tries to bind pre-defined namespace with URI http://www.w3.org/XML/1998/namespace which should always be bound as xml and neither need to be redefined nor legal to rebind. Woodstox parser does properly detect the issue.
This occurs both for attributes and elements.

[cowtowncoder]

Looks like this occurred only in case where no other bindings existed yet (and there was no bindings object); need to ensure check for xml is done even in such case.