This ensures that _append, _prepend, overrides, etc are functional when used
on sstate variables (e.g. SSTATE_DIR).
[YOCTO #7564]
(Bitbake rev: 2e683c25b856b431198573f7f352d841587275e6)
Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>