NEW YORK (Reuters Breakingviews) - When there’s a $44 billion merger in the offing, it’s natural that lots of investors kick the tires. With Elon Musk’s personal buyout of Twitter, however, it’s tough for managers of other people’s money – like private equity firms, for example – to justify investing alongside the Tesla chief executive. Morgan Stanley has spearheaded a $13 billion debt package for the acquisition.