* Consul Service meta wrongly computes and exposes non_voter meta
In Serf Tags, entreprise members being non-voters use the tag
`nonvoter=1`, not `non_voter = false`, so non-voters in members
were wrongly displayed as voter.
Demonstration:
```
consul members -detailed|grep voter
consul20-hk5 10.200.100.110:8301 alive acls=1,build=1.8.4+ent,dc=hk5,expect=3,ft_fs=1,ft_ns=1,id=xxxxxxxx-5629-08f2-3a79-10a1ab3849d5,nonvoter=1,port=8300,raft_vsn=3,role=consul,segment=<all>,use_tls=1,vsn=2,vsn_max=3,vsn_min=2,wan_join_port=8302
```
* Added changelog
* Added changelog entry
