Taking run-postinsts and building for two machines which have different
OVERRIDES leads to two different sets of stamps for an allarch package.
We don't need to depend on OVERRIDES in these classes, the end resulting
variables are good enough. We can therefore exclude the dependency
and allow a single package to be generated for run-postinsts.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
