CookerParser.shutdown code doesn't do all required work to shutdown
parser processes. As a result bitbake hangs if interrupted during
parsing. Putting None into the parser_quit queue should fix this issue
as it makes parsers to quit main loop.
(Bitbake rev: f67307977e8f089ce6d208d3e9de2a6a1768757e)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>