When IO queues are used for parallelized management operations,
e.g. changing cleaning policy, a deadlock may occur due to global
metadata lock interfering with taking request from IO queue,
as they might be run on the same thread. As a workaround using
a management queue specifically for such operations eliminates
this problem.
Signed-off-by: Rafal Stefanowski <rafal.stefanowski@huawei.com>