Fix rfb handshake after r355301.

[araujo]

Summary

The change to the defintion of 'const char *vbuf' in rfb.c is wrong.
The protocol version string must be send as "RFB 003.008\n" and not as
"RFB 003.008\n\r", otherwise the VNC client isn't able to complete the
handshake (it doesn't recognize the protocol version). While it stays
connected, it doesn't show anything.

Submitted by: Yamagi [e-mail]

[rgrimes]

Good catch, thank you Yamagi and Marcelo

[araujo]

It was committed already by @jhb at: https://svnweb.freebsd.org/changeset/base/355912