The problem was that "s" would not be marked as synced-with if it came from
shard != 0.
As a result, mutation using that schema would fail to apply with an exception:
"attempted to mutate using not synced schema of ..."
The problem could surface when altering schema without changing
columns and restarting one of the nodes so that it forgets past
versions.
Fixes#1258.
Will be covered by dtest:
SchemaManagementTest.test_prepared_statements_work_after_node_restart_after_altering_schema_without_changing_columns
(cherry picked from commit 8703136a4f)
f796d8081b