block: Fix locking for bdrv_reopen_queue_child()

block: Fix locking for bdrv_reopen_queue_child()

Callers don't agree whether bdrv_reopen_queue_child() should be called
with the AioContext lock held or not. Standardise on holding the lock
(as done by QMP blockdev-reopen and the replication block driver) and
fix bdrv_reopen() to do the same.

Signed-off-by: Kevin Wolf <[email protected]>
Message-Id: <20221118174110[email protected]>
Reviewed-by: Hanna Reitz <[email protected]>
Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>