By Tom Hals WILMINGTON, Del. (Reuters) -Billionaire Elon Musk accused Twitter Inc of fraud by concealing serious flaws in the social media company’s data security, which the entrepreneur said should allow him to end his $44 billion deal for the company, according to a Thursday court filing. Musk, the world’s richest person, amended his previously filed lawsuit by adopting allegations by a Twitter whistleblower, who told Congress on Tuesday of meddling on the influential social media platform by foreign agents. The chief executive of electric vehicle maker Tesla Inc also alleged that Twitter hi…