LUDOC-547: max statahead_max no longer 8192

LUDOC-547: max statahead_max no longer 8192

Fixes: e10bf68d7c3e ("LU-14361 statahead: regularized fname statahead pattern")
Fixes: b52a1221bf1d ("LU-11079 llite: control concurrent statahead instances")
Fixes: 164231a7a29b ("LU-11079 llite: control concurrent statahead instances")
Signed-off-by: Laura Hild <lsh@jlab.org>
Change-Id: I66c5ff5f654a6b9ec61e9bdae7db80689302e036
Reviewed-on: https://review.whamcloud.com/c/doc/manual/+/57403
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>