EX-6269 obd: add 'lvl' for best and fast

EX-6269 obd: add 'lvl' for best and fast

'best' and 'fast' compression types must also set a level,
because not all levels are supported by all algorithms.

Rather than trying to be clever, just use simple universally
supported values, except for lz4fast, where we special case
this, because otherwise '0' is the slowest setting (and
lz4fast is likely to remain our default fastest).

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I7c29659d4f027af2e44285ae38e4c9d91e35509a
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53600
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>