quake: let use role if we cannot set name

Some terminals do not allow to set name (like xfce4-terminal). In this
case, use the role.

rc/quake.lua

@@ -3,6 +3,7 @@ local quake = loadrc("quake", "vbe/quake")
 local quakeconsole = {}
 for s = 1, screen.count() do
    quakeconsole[s] = quake({ terminal = config.terminal,
+                             argname = "--role %s",
 			     height = 0.3,
 			     screen = s })
 end