LU-930 doc: remove mention of no_precreate option

LU-930 doc: remove mention of no_precreate option

The no_precreate mount option and obdfilter tunable parameter is
deprecated, so remove it from the man pages.  It will continue
to work for the next few Lustre releases, but will be removed in
Lustre 2.21.

Test-Parameters: trivial
Fixes: 614a76c466 ("LU-930 doc: document no_create mount option")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ibe49b4c8aea667b84890879171098787933f8ba6
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59952
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Frederick Dilger <fdilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>