[Fix] Use Host if IPv6 address hostname
[Fix] Use Host if IPv6 address hostname

Fix for a part of pull request #264.

2Toad/websocket-sharp,2Toad/websocket-sharp,sta/websocket-sharp,2Toad/websocket-sharp,jogibear9988/websocket-sharp,jogibear9988/websocket-sharp,2Toad/websocket-sharp,sta/websocket-sharp,jogibear9988/websocket-sharp,sta/websocket-sharp,jogibear9988/websocket-sharp,sta/websocket-sharp