Close and destroy sockets on connection error.

[rumata28]

Add sock.end and sock.destroy calls for sock.once('error', ...)
event handler and for c.open(fields, ...) callback - just like it was
done for connection timeout callback.

Resolves #513

[rumata28]

Sorry, tests failed.
I use Windows as a development machine, need to figure it out how to install everything.
Just checked that the change fixes issue for my tests, locally.

[rumata28]

Close it, will reopen once I make it work.