EX-7601 osc: give compress_request explicit success

EX-7601 osc: give compress_request explicit success

Compress_request has explicit failure handling, but the
success handling just follows the failure handling.  This is
confusing - on failure, we do:
page_count = *pcount
then immediately do:
*pcount = page_count

It also sets *orig_pga = pga on success OR failure, which
is wrong because compress_request may have modified pga and
then failed.

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I121ec71cfe35babc4a572951e93f7581887ade80
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53119
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>