Replace parking_lot::Mutex in postoffice (#1496)
Replace parking_lot::Mutex in postoffice (#1496)

* Replace std::Mutex in postoffice

Signed-off-by: Michael Pankov <e274eeff768c6396088ec6eb091f4bf4d47ab1e0@michaelpankov.com>

* Format code

Signed-off-by: Michael Pankov <e274eeff768c6396088ec6eb091f4bf4d47ab1e0@michaelpankov.com>

intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre