LU-15314 utils: set default max-inherit to 3

LU-15314 utils: set default max-inherit to 3

Change LMV_INHERIT_DEFAULT from 0 to 3. So that the default stripe
policy of dir will not be inherited unlimited and reduce performance
unexpectly.

Lustre-change: https://review.whamcloud.com/45874
Lustre-commit: 956b4b1e0d9f18c6fe62d84e1c20268363b8159b

Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial
Change-Id: I67ef540046867ccec7ccc3aab035edbff95874c3
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/46208
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>