cherokee: fix SRC_URI

  (original commit: 70bc5626b3e6c6bc90b8845f8e7e48f45bf57174)

The package is no longer available in the official cherokee site,
so download it from a mirror.

Signed-off-by: Javier Viguera <javier.viguera@digi.com>
Signed-off-by: Eric Bénard <eric@eukrea.com>