Debtor ineligible for discharge because of § 1328(f) can strip off wholly unsecured lien on primary residence. “[T]he parties agree that the anti-modification provision [§ 1322(b)(2)] does not apply because the junior lien held by First National Bank against Debtor’s Residence is wholly unsecured. . . . [Section] 1325(a) does not preclude Debtor from stripping off the lien. . . . [Section] 1328(f)(1) is clear: it prohibits only ‘a discharge of all debts provided for in the plan.’ . . . [S]tripping off a lien is not the same thing as being discharged from personal liability for the debt underlying that lien. . . . [B]ankruptcy courts should carefully scrutinize a Chapter 20 debtor’s plan to ensure that it was proposed in good faith. However, the fact that some Chapter 20 debtors may not propose their plans in good faith is not reason to bar every Chapter 20 debtor from utilizing the lien stripping tools made available to him by Congress.”