Remove net lock from DIOCGETRULESET and DIOCGETRULESETS

Remove net lock from DIOCGETRULESET and DIOCGETRULESETS

Both walk the list of rulesets aka. anchors, to yield a total count and
specific anchor name, respectively.  Same access, different copy out.

pf_anchor_global are contained within pf_ioctl.c and pf_ruleset.c and
fully protected by the pf lock, as is pf_main_ruleset and its pf.c usage.

Rely on and assert for pf lock alone.  'pfctl -sr' on 60k unique rules gets
noticably faster, around 2.1s instead of 3.5s.

OK sashan