Trying to have a new python process forked off an original doesn't work
out well and ends up having race issues. To avoid this, exec() a new
bitbake server process. This starts with a fresh python interpreter
and resolves various atexit and other multiprocessing issues once
and for all.
(Bitbake rev: 9501dd6fdd7a7c25cbfa4464cf881fcf8c049ce2)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
