LU-3789 mgs: Add deprecation warning for "lctl conf_param"

LU-3789 mgs: Add deprecation warning for "lctl conf_param"

lctl set_param -P has been added with LU-3155. Old mechanism
(lctl conf_param) should be deprecated.

This patch adds warnings since 2.7.53 and disable lctl set_param
option since 3.0.53

Xyratex-bug-id: MRP-272
Signed-off-by: Artem Blagodarenko <artem_blagodarenko@xyratex.com>
Change-Id: I37479a333869de1d10b74b623bd4d921774664e8
Reviewed-on: http://review.whamcloud.com/7436
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>