net: http: One extra byte was sent in last chunk

There was one extra byte sent in last chunk which caused
this error to be printed by curl

  * Illegal or missing hexadecimal sequence in chunked-encoding
  * stopped the pause stream!
  * Closing connection 0
  curl: (56) Illegal or missing hexadecimal sequence in chunked-encoding

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>