Add exception class for attempting to create duplicate Connector instances.
Add exception class for attempting to create duplicate Connector instances.

vishwaprakashmishra/xmatrix,TouK/vumi,TouK/vumi,harrissoerja/vumi,vishwaprakashmishra/xmatrix,vishwaprakashmishra/xmatrix,TouK/vumi,harrissoerja/vumi,harrissoerja/vumi