CrushWrapper: pick a ruleset same as rule_id

Originally in the add_simple_ruleset funtion, the ruleset_id
is not reused but rule_id is reused. So after some add/remove
against rules, the newly created rule likely to have
ruleset!=rule_id.

We dont want this happen because we are trying to hold the constraint
that ruleset == rule_id.

Signed-off-by: Xiaoxi Chen <xiaoxi.chen@intel.com>
(cherry picked from commit 78e84f34da83abf5a62ae97bb84ab70774b164a6)

Conflicts:
	src/test/erasure-code/TestErasureCodeIsa.cc

Fixes: #9675
Merge pull request #2776 from ceph/wip-9675.firefly

CrushWrapper: pick a ruleset same as rule_id

Reviewed-by: Samuel Just <sam.just@inktank.com>