scribble: fix binding search for phase 1 through initial import
scribble: fix binding search for phase 1 through initial import

Changing the implementation of `racket' in terms of `racket/base'
exposed this bug.

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket