This simplifies a duplicated iteration pattern in the calling code.
It also frees the first-node function to raise an Error (which the
iterator now catches) if it finds no node, where it used to return
False (instead of a node, so other code using it would raise confusing
errors from trying to use False as a node, where now it'll get a clear
Error about a missing node). There were also no callers passing an
empty name, so the test for matching nodes (here moved to its own
short function) didn't need to handle that as a special case.
Change-Id: Ife6cad8943cf5dc2c6ed68429d4a217cb9bea446
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
e93af7dafd