distributed_loader: make shutdown clean by properly handling compaction_stopped exception
distributed_loader: make shutdown clean by properly handling compaction_stopped exception

Today, when resharding is interrupted, shutdown will not be clean
because stopped exception interrupts the shutdown process.
Let's handle stopped exception properly, to allow shutdown process
to run to completion.

Refs #9759

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>
Message-Id: <20211221175717.62293-1-1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla