LU-1303 osp: OSP logging functionality

LU-1303 osp: OSP logging functionality

OSP writes unlink and setattr llogs and tracks corresponding commits
at OST side, then cancel llog records locally

Add missed obd_device methods and import event handling

Signed-off-by: Mikhail Pershin <tappro@whamcloud.com>
Change-Id: I63ecc975e483a7f9caac9554cc15c3a4fb4a6e6d
Reviewed-on: http://review.whamcloud.com/4095
Reviewed-by: wangdi <di.wang@whamcloud.com>
Tested-by: Hudson
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>