cc-proxy/cc-shim high availability

[sameo]

If cc-proxy crashes:

1. all cc-shim instances terminate.
2. cc-proxy will not be able to restore its internal state after restarting.

We need to work on:

1. Have cc-shim retry connecting to the proxy when the socket is closing/disappearing
2. Have cc-proxy re-build all its states when restarting, based on the stored information

[laijs]

the virtio-serial is not package based transport, it seams hard to find the message header when cc-proxy re-connect to hyperstart.

[sameo]

This issue was moved to clearcontainers/proxy#4