LU-10005 osp: cache non-exist EA

LU-10005 osp: cache non-exist EA

OSP should also cache non-exist EA, otherwise
it will keep sending RPC to try to get remote
non-exist EA.

So if default stripe EA does not exist on root
MDT, file creation on non-root MDT will always
try to send extra OSP RPC to get the EA.

This patch also fixes a LFSCK bug that may cause
the LFSCK repaired items to be counted repeately.

Test-Parameters: mdtfilesystemtype=ldiskfs ostfilesystemtype=ldiskfs mdscount=2 mdtcount=4 testlist=sanity-lfsck,sanity-lfsck,sanity-lfsck
Lustre-change: https://review.whamcloud.com/29078
Lustre-commit: b2fa448050aff0b5230c8cc94e8baf848fbb4ded

Signed-off-by: Di Wang <di.wang@intel.com>
Change-Id: Ie9c8cb5fd54e404f1af97de47e809f6f96de8d86
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/30585
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>