Fix keepalive

[Taknok]

Hi,

Related issue: #314

In a nutshell: The client keep-alive configuration is not passed to tunnel config. Thus, the tunnel does not enter the keep-alive function.

Solution:
Pass the client config keepalive to the tunnel config.

Examples:

go build && ./chisel client --keepalive 1s -v --auth XXX https://server.com socks

Before (exemple-before branch):

2021/11/27 13:15:36 client: Connecting to wss://server.com:443
2021/11/27 13:15:36 client: tun: proxy#127.0.0.1:1080=>socks: Listening
2021/11/27 13:15:36 client: tun: Bound proxies
2021/11/27 13:15:37 client: Handshaking...
2021/11/27 13:15:37 client: Sending config
2021/11/27 13:15:37 client: Connected (Latency 49.781634ms)
2021/11/27 13:15:37 client: tun: SSH connected

After (exemple-after branch):

021/11/27 13:18:47 client: Connecting to wss://server.com:443
2021/11/27 13:18:47 client: tun: proxy#127.0.0.1:1080=>socks: Listening
2021/11/27 13:18:47 client: tun: Bound proxies
2021/11/27 13:18:47 client: Handshaking...
2021/11/27 13:18:48 client: Sending config
2021/11/27 13:18:48 client: Connected (Latency 45.692712ms)
2021/11/27 13:18:48 client: tun: SSH connected
Hello World!
Hello World!
Hello World!
Hello World!
Hello World!
Hello World!
^C

Thank you for this amazing tool !

[jpillora]

Thanks!