lower version, for example 2.6.8
```properties
dubbo.provider.version=1.0
```

2.7.6 failed to recognize the provider url with 'default.version=1.0' key,  it only takes 'version.1.0' into consideration.

if (ip == null) {
            ip = NetUtils.getIpByHost(host);
        }
        return ip;
    }
    public int getPort() {
        return port;
    }
    public URL setPort(int port) {
        return new URL(protocol, username, password, host, port, path, getParameters());
    }
    public int getPort(int defaultPort) {
        return port <= 0 ? defaultPort : port;
    }
    public String getAddress() {
        if (address == null) {
            address = getAddress(host, port);
        }
        return address;
    }
    public URL setAddress(String address) {
        int i = address.lastIndexOf(':');
        String host;
        int port = this.port;
        if (i >= 0) {
            host = address.substring(0, i);
            port = Integer.parseInt(address.substring(i + 1));
        } else {
            host = address;
        }