### Peer is still banned, allthough ban endtime has been reached

Here the log line of the banned peer:

`2017-11-04 16:12:03 Misbehaving: 212.203.47.xxx:61681 peer=56085 (0 -> 100) BAN THRESHOLD EXCEEDED`

In the debug connection window, the peer shows up as banned, with the ban endtime of 2017-11-05 17:12:03 CET, see screenshot (marked blue peer).

Then today, 2017-11-05 around 10 o clock CET, I stopped bitcoind 0.15.0.1, replaced the binaries with 0.15.1rc1 and started bitcoind again.

Now, as the time of the screenshot is 17:40 CET, the ban endtime had been reached, but the peer does still show up as banned.

Edit: Situation unchanged at 20:46 CET.

### Expected behaviour
Peer disappears from the "Banned peers" list, when ban endtime has been reached.

### Actual behaviour
Peer does not disappear from the "Banned peers" list, allthough ban endtime has been reached and exceeded.

### Screenshots.
![bildschirmfoto](https://user-images.githubusercontent.com/8447873/32416947-f2e0129a-c251-11e7-9c92-528f0ff3ae5d.png)

### What version of bitcoin-core are you using?
0.15.0.1 / 0.15.1rc1

### Machine specs:
Linux amd64

port.c_str(), port.c_str(), lanaddr, strDesc.c_str(), "TCP", 0);
#else
                
                r = UPNP_AddPortMapping(urls.controlURL, data.first.servicetype,
                                    port.c_str(), port.c_str(), lanaddr, strDesc.c_str(), "TCP", 0, "0");
#endif
                if(r!=UPNPCOMMAND_SUCCESS)
                    LogPrintf("AddPortMapping(%s, %s, %s) failed with code %d (%s)\n",
                        port, port, lanaddr, r, strupnperror(r));
                else
                    LogPrintf("UPnP Port Mapping successful.\n");
                MilliSleep(20*60*1000); 
            }
        }
        catch (const boost::thread_interrupted&)
        {
            r = UPNP_DeletePortMapping(urls.controlURL, data.first.servicetype, port.c_str(), "TCP", 0);
            LogPrintf("UPNP_DeletePortMapping() returned: %d\n", r);
            freeUPNPDevlist(devlist); devlist = nullptr;
            FreeUPNPUrls(&urls);
            throw;
        }
    } else {
        LogPrintf("No valid UPnP IGDs found\n");
        freeUPNPDevlist(devlist); devlist = nullptr;
        if (r != 0)
            FreeUPNPUrls(&urls);
    }
}
void MapPort(bool fUseUPnP)