compound set will select runs from all of its managed sets, so let's
adjust select_sstable_runs() to only return runs which belong to it.
without this adjustment, selection of runs would fail because
function would try to unconditionally retrieve the run which may
live somewhere else.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210312042255.111060-3-raphaelsc@scylladb.com>