unset VAR
will clear variable VAR
unset VAR[flag]
will clear flag "flag" from var VAR
(Bitbake rev: bedbd46ece8d1285b5cd2ea07dc64b4875b479aa)
Signed-off-by: Jérémy Rosen <jeremy.rosen@openwide.fr>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>