Prevent multiple connections to the same peer

Not sure if this is a clearnet/brontide issue or peers are just connecting to each other redundantly, but I have a node that has two connections from easyhandshake, one inbound and one outbound:

```
{
"id": 182,
"addr": "165.22.151.242:43298",
"addrlocal": "64.227.15.172:12038",
"services": "00000003",
"servicenames": [
"NETWORK",
"BLOOM"
],
"relaytxes": true,
"lastsend": 1597955469,
"lastrecv": 1597955469,
"bytessent": 888009,
"bytesrecv": 926672,
"conntime": 277062,
"timeoffset": -42,
"pingtime": 0.076,
"minping": 0.065,
"version": 3,
"subver": "/hsd:2.2.0/easyhandshake.com/",
"inbound": true,
"startingheight": 28849,
"besthash": "000000000000000a2e717f876657fd7bfaa54cb3c2ae86d76c18b5bf44fcafac",
"bestheight": 29301,
"banscore": 0,
"inflight": [],
"whitelisted": false
},
{
"id": 199,
"addr": "165.22.151.242:12038",
"addrlocal": "64.227.15.172:49104",
"services": "00000003",
"servicenames": [
"NETWORK",
"BLOOM"
],
"relaytxes": true,
"lastsend": 1597955465,
"lastrecv": 1597955465,
"bytessent": 903240,
"bytesrecv": 886301,
"conntime": 277036,
"timeoffset": -16,
"pingtime": 0.077,
"minping": 0.067,
"version": 3,
"subver": "/hsd:2.2.0/easyhandshake.com/",
"inbound": false,
"startingheight": 28849,
"besthash": "000000000000000a2e717f876657fd7bfaa54cb3c2ae86d76c18b5bf44fcafac",
"bestheight": 29301,
"banscore": 0,
"inflight": [],
"whitelisted": false
},

```