LU-7004 utils: defer conf_param deprecation

LU-7004 utils: defer conf_param deprecation

Since there has been relatively little testing of "lctl set_param -P"
and the test scripts and documentation have not been converted from
using "lctl conf_param" yet, I'm deferring the conf_param deprecation
warning to 2.8.53 (essentially 2.9.0) to give time for this change.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I6e879aaf5f9c9e1434f52a7274c663096ceb35b5
Reviewed-on: http://review.whamcloud.com/15979
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Artem Blagodarenko <artem.blagodarenko@seagate.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>