LU-14603 ptlrpc: quiet messages for unsupported opcodes

LU-14603 ptlrpc: quiet messages for unsupported opcodes

Quiet messages for OST_FALLOCATE and OST_SEEK RPCs that can
be sent from 2.14.0 clients.

Lustre-change: https://review.whamcloud.com/43257
Lustre-commit: TBD (from c7427f6618308996e76718baeba492c0b09dd5b3)

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I35496168e3aa29ecb06076654ef0aa97ba2540e5
Reviewed-on: https://review.whamcloud.com/43260
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: Stephane Thiell <sthiell@stanford.edu>
Reviewed-by: Oleg Drokin <green@whamcloud.com>