LU-6271 osc: handle osc eviction correctly

LU-6271 osc: handle osc eviction correctly

Cleanup everything if an OSC is being evicted.

Group lock is not well supported yet.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I24f815a9a1bf13cb565109b2dae7b4d07b57f921
Reviewed-on: http://review.whamcloud.com/14989
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>