keyboard clone handling in x2go mode incorrect

[uli42]

If run as x2goagent we check if the requested keyboard is null/null and then create the keyboard directory to prevent x2gosetkeyboard from setting a keyboard. Instead x2goagent handles this itself.

However, if the user configures "do not set keyboard" or specifies an explicit keyboard in the x2goclient session configuration then startx2goagent will already create a keyboard directory (in a script running in parallel to the x2goagent startup). x2goagent then reports that it could not create the keyboard directory.

So this must be revisited (or even be dropped)