Fix CRIT where local_addr.address is null

Fixes:

````
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core] TypeError: Cannot read property 'address' of null
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at setupClient (/usr/lib/node_modules/Haraka/connection.js:71:41)
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at new Connection (/usr/lib/node_modules/Haraka/connection.js:175:5)
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at Object.exports.createConnection (/usr/lib/node_modules/Haraka/connection.js:181:13)
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at /usr/lib/node_modules/Haraka/server.js:152:18
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at Server.<anonymous> (/usr/lib/node_modules/Haraka/tls_socket.js:214:9)
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at Server.EventEmitter.emit (events.js:96:17)
Mar 18 15:06:37 mail1-ec2 haraka[1915]: [CRIT] [-] [core]     at TCP.onconnection (net.js:1038:8)
````

I suspect it's caused by the client dropping the connection before the method returns.