LU-1110 fid: add full support for open-by-fid

LU-1110 fid: add full support for open-by-fid

Op-by-fid which involves parent change are not permitted:
        link/unlink/rename/create/open(CREATE)
return -EPERM directly in case dt operations are triggered, but obf
object doesn't have disk object, which will panic.

Add more sanity tests for op-by-fid.

Signed-off-by: Lai Siyao <laisiyao@whamcloud.com>
Change-Id: I10869923e861ac0165886a48880f58e1269554ec
Reviewed-on: http://review.whamcloud.com/2224
Reviewed-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-by: wangdi <di.wang@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Faccini Bruno <bruno.faccini@bull.net>
Reviewed-by: Oleg Drokin <green@whamcloud.com>