This trivial patch is setting "timeout tunnel" in haproxy's
configuration for spicehtml5proxy. This option extends time
when spice's websocket connection is closed, so spice will
not be freezed. Default value is set to 1h as it is in novnc.

Closes-Bug: #1938549
Change-Id: I3a5cd98ecf4916ebd0748e7c08111ad0e4dca0b2