frontend: Disabling WAN options for SPICE doesn't work

SPICE -> Enable WAN options causes 16bit color depth get kept for every console
opening for whole browser session even after disabling this option in the
console dialog.

The problem was caused by not resetting the ColorDepth and DisabledEffects
values after disabling WAN options to default values.

Change-Id: Ie64779658796243f0182ac1209d9f5640b4370fc
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=913183
Signed-off-by: Frantisek Kobzik <fkobzik@redhat.com>