staging: lustre: lmv: Do not revalidate stripes with master lock

Do not revalidate slave stripes while holding master lock.
Otherwise if the revalidating slaves are blocked, then the
master lock can not be released in time.

Remove some unnecesary merging in ll_revalidate_slave(), and
the attributes will be stored in each stripe, only
merging them if required.

Signed-off-by: wang di <di.wang@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6088
Reviewed-on: http://review.whamcloud.com/13432


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>