fetch2: Clean up some url parameters to functions

urldata contains the url so we might as well stop passing around
pointless function parameters. This was done for legacy reasons but
its time to clean this mess up.

This is a first step in cleanup and is a standalone patch but there is
more to be done in a second patch.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
fetch2: Stop passing around the pointless url parameter

There is no good reason to keep passing around the url parameter when
its contained within urldata (ud). This is left around due to
legacy reasons, some functions take it, some don't and its time
to cleanup.

This is fetcher internal API, there are a tiny number of external users
of the internal API (buildhistory and distrodata) which can be fixed up
after this change.

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