FRANKFURT (Reuters) -The European Central Bank will fight any “disorderly” blowout in the borrowing costs of more indebted euro zone nations, but its response should be tailored and there is no need to pre-announce a new tool, ECB board member Isabel Schnabel said on Tuesday. The ECB last week said it would not tolerate fragmentation that would impair monetary policy but failed to outline the tools it would use, spooking investor who then sold off Italian debt, raising debt sustainability questions. “There can be no doubt that, if and when needed, we can and will design and deploy new instrume…