wget: Add localpaths method which gives localpath with history

wget: Add localpaths method which gives localpath with history

In some cases for cache purpoes we not only need to know which file
is going to be used but also which paths were considered. Add a
localpaths method which includes the history.

The core which() funciton already supports this, this just extends
the function to preserve the extra data we need. localpath becomes
just a special case of the case with history.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>