Oh, she's got a big enough chip on her shoulder to have said this stuff. Wouldn't surprise me a bit. Whether she was dumb enough to spew this stuff in front of a camera is another matter. Rumors don't mean a thing. Without an actual tape this is a non story.
Remember, Larry Johnson is a Hillary guy. It would be in his interest to make one last effort to sew doubt out there about Obama's electability. So he has a motive to make stuff up. Whether that is worth it to him to destroy what shred of credibility he has left by making something up that doesn't come to pass is also a question. Maybe the guy is just crazy.
Again, rumors don't mean jack and are a waste of time.
I seriously doubt she would use the term whitey. She's too educated to talk like that, even if she isn't thrilled about white people. That's how white racists think black people talk, based on their extensive knowledge of black culture gathered from watching hip-hop videos and UPN sitcoms.