LU-10948 mdt: New connect flag for non-open-by-fid lock request

LU-10948 mdt: New connect flag for non-open-by-fid lock request

While we removed the 2.1 check for open by fid when open
lock is requested, when you talk to old servers that don't
have that patch - they get an open error, so introduce a compat
flag.

Change-Id: I94d50ad98a2828519853a35fa90c5063adf2feab
Fixes: 41d99c4902 ("LU-10948 llite: Introduce inode open heat counter")
Signed-off-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/43907
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>