Bitbake now only processes overrides which are lowercase since
this allows variables like SRC_URI not to pollute the cache.
There was a corner case where XXX_append_SomeThing was still being
processed (yet XXX_append_SomeThing_SomeOtherThing would not be).
This patch ensures we're consistent and only process lowercase
_append/_prepend and _remove operators too.
(Bitbake rev: 6eb56624e6d8dc1944e559b4f6584bfe66f566ba)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>