sstables/compaction_manager: Don't perform upgrade on shared SSTables
sstables/compaction_manager: Don't perform upgrade on shared SSTables

compaction_manager::perform_sstable_upgrade() fails when it feeds
compaction mechanism with shared sstables. Shared sstables should
be ignored when performing upgrade and so wait for reshard to pick
them up in parallel. Whenever a shared sstable is brought up either
on restart or via refresh, reshard procedure kicks in.
Reshard picks the highest supported format so the upgrade for
shared sstable will naturally take place.

Fixes #5056.

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>
Message-Id: <20190925042414.4330-1-1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>

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