Cybill Shepherd is turning her portrayal of Martha Stewart into a habit. CBS has slapped together a sequel Martha movie called “Martha: Behind Bars” and may air it during May sweeps. Actually, it’s not strictly a sequel since the first Martha movie aired on NBC and was based on the book “Martha, Inc.” The producer of the CBS telepic has said “I don’t do schlocky things” (a critique of the last movie perhaps?). Perhaps Shepherd will get a chance to put in a more understated performance this time. (I still think Candice Bergen would be much better as Martha.)