ThaliCore: TCPListener "Address already in use" doesn't trigger the retry logic

[enricogior]

In ThaliCore we added a retry logic for transient errors, we need to figure out if we can recover from this error:

[ThaliCore] TCPListener.startListeningForConnections(on:connectionAccepted:completion:)
failed, error:Error Domain=NSPOSIXErrorDomain Code=48 "Address already in use" 
UserInfo={NSLocalizedDescription=Address already in use, 
NSLocalizedFailureReason=Error in bind() function}
2017-07-18 07:16:46 - DEBUG thaliMobileNativeWrapper: 'multiConnectResolved: 
{"syncValue":"0","error":"Connection could not be established","portNumber":0}'

[enricogior]

Another issue with this error is that TCPListener.startListeningForConnections() doesn't return an error to its direct caller, in this case is BrowserRelay.openRelay(), therefore the relay is not released.

[enricogior]

Note: we use the GCDAsyncSocket library that seems to set SO_REUSEADDR
We need to verify if that covers our case.