Change error message for IllegalArgumentException. It's not just an SSL issue....

Change error message for IllegalArgumentException. It's not just an SSL issue. Also, didn't realize this at the time, but a switch that does not support table features will not have the table-miss flows inserted at present. As a workaround, we don't check for table existance before adding the flows. This might result in a flow-add error, but it's better than not having the flow when you would expect it. TODO: Have a flag in the switch that denotes whether or not table features were supported.