Fix (get '(+ 2 2) 'text) bug.

Try:

    $ pil
    : (get '(+ 2 2) 'text)
    -> NIL
    : (bye)

But:

    $ emulisp/piljs
    : (get '(+ 2 2) 'text)
    -> (+ 2 2)
    : (bye)

Not sure it was the good way to fix this. I just voodoo'ed it.
Also maybe we could add a test like `'(= NIL (get '(+ 2 2) 'text))`. But where exactly?