If you send back a string here you get "TypeError: 'str' does not
support the buffer interface" errors in bitbake-cookerdaemon.log and
"IncompleteRead(0 bytes read, 22 more expected)" errors on the client
side.
(Bitbake rev: 0d659a7dfe5fb096f8aa4380320f9e2a464b3cb5)
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>