This variable hasn't been used for a *long* time, remove it from bitbake.conf.
(From OE-Core rev: 91c1235a1614a0b097f0a9efdd13436412a35387)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>