handle connection error

Hello,

I'm writing nagios check based on your lib, and I was stuck getting errors:
to reproduce: just try to connect to non-listening port
Exception AttributeError: "'_SocketIO' object has no attribute 'connection'" in <bound method _SocketIO.__del__ of <socketIO_client._SocketIO object at 0x15acf90>> ignored
Exception AttributeError: "'SocketIO' object has no attribute '_socketIO'" in <bound method SocketIO.__del__ of <socketIO_client.SocketIO object at 0x1587990>> ignored
so, I tried to fix that, thus added handling exception thrown by requests module and added checks for attributes.
I just started few days ago with python, so may be my fix is not proper.
If it is not - let me know, I'll create issue with description, so someone more experienced can fix that some day.