fetch: use orig localpath when calling orig method

fetch: use orig localpath when calling orig method

When a mirror tarball is fetched, the original fetch method is called, which
unpacks the mirror tarball. After the original method is called, it checks the
localpath of the mirror tarball rather than the clone path, which isn't ideal,
particularly if the mirror tarball was removed due to being out of date. We
know the original fetch method will do what it needs to do to get its content
in the form it needs from the mirror tarball, so we can use its localpath
instead.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Awais Belal <awais_belal@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>