LU-15913 mdt: disable parallel rename for striped dirs

LU-15913 mdt: disable parallel rename for striped dirs

Parallel rename should not be done within striped directories to
avoid remote updates.  These are like cross-directory renames.

Add tunables for parallel directory rename in case of problems.
These can be configured separately for files and directories.

    mdt.*.enable_parallel_rename_dir
    mdt.*.enable_parallel_rename_file

Lustre-change: https://review.whamcloud.com/47593
Lustre-commit: f238540c879dc668e18cf99cba62f117ccae64d6

Fixes: 90979ab390 ("LU-12125 mds: allow parallel directory rename")
Fixes: d76cc65d5d ("LU-12125 mds: allow parallel regular file rename")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I384976cd1c9f401169336ee7a479ba0e3dd9f4ee
Reviewed-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/48124
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>