Some small tidy-ups
Some small tidy-ups

List prepublish_plugins before postbuild_plugins, since that is the
order they run in.

Remove unnecessary code.

Signed-off-by: Tim Waugh <fe049355006bf7fdd11c5e47ffe7a5032af30704@redhat.com>

bfontecc007/osbs-client,bfontecc007/osbs-client,DBuildService/osbs-client,projectatomic/osbs-client,projectatomic/osbs-client,vrutkovs/osbs-client,DBuildService/osbs-client,vrutkovs/osbs-client