There are some cases where the metadata needs to check if a variable
has any overrides set, even if they are currently inactive. That code
currently pokes into datastore internals. Add API instead to replace
and avoid that.
(Bitbake rev: c885e5542dcf760b8fc5881e385abb4a10020874)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>