Description of problem:
spice-server uses exclusively TLS version 1.0 no matter what version(s) the client advertises. This is plain wrong as TLS 1.0 shows its age and the best version supported by both parties should be used.

Version-Release number of selected component (if applicable):
spice-gtk-0.20-11.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. run spice-server:
qemu-kvm -monitor stdio -vga qxl -spice disable-ticketing,x509-dir=<dir>,tls-port=<port>
2. start wireshark capture on the port
3. connect to the port using s_client set to respective TLS versions:
openssl s_client -CAfile /path/to/ca.pem -connect <fqdn>:<port> <TLS_VERSION>
where TLS version is:
    * -tls1 for TLS 1.0
    * -tls1_1 for TLS 1.1
    * -tls1_2
4. look in the wireshark traces for ServerHello or "Client Key Exchange" messages.
If you can't see ClientHello message, right-click some captured packet, click Decode As..., go to Transport tab and select SSL.

Actual results:
TLSv1: connection is successfully established (good)
TLSv1.1: connection is terminated right after ClientHello packet
TLSv1.2: connection is terminated right after ClientHello packet

Expected results:
connection is successfully established when using any of TLS versions above

Additional info:
current version of spice-gtk is also tied to TLS 1.0 so it can't be used to test spice-server fix at the moment.

Wireshark protocol markings may be a bit misleading: there are two places where the version is specified in ClientHello message:
Secure Sockets Layer
  TLSv<misleading_version> Record Layer: Handshake Protocol: ClientHello
    ...
    Version: TLS 1.0 (0x301)  <----  set to the TLS 1.0 for TLS 1.0-1.2
    ...
    Handshake Protocol: ClientHello
      ...
      Version: TLS 1.2 (0x303)  <--- this must be set to version 1.1 or 1.2
                                     in order to verify the bug