By Sheila Dang and Greg Roumeliotis (Reuters) -Twitter Inc anticipates a shareholder vote on its $44 billion sale to Elon Musk could come by early August, as it continues to work constructively to complete the deal with the world’s richest person, the social media company’s top executives told employees on Wednesday. Musk’s lawyers warned Twitter on Monday that he might walk away from the acquisition if the company fails to provide the data he seeks on spam and fake accounts. Twitter has said it is continuing to share information with Musk. Part of that data is the “firehose,” a set comprising…