By Gibran Naiyyar Peshimam, Asif Shahzad and Mubasher Bukhari LAHORE (Reuters) -Former Pakistan Prime Minister Imran Khan was shot in the shin on Thursday when his anti-government protest convoy came under attack in the east of the country in what his aides said was a clear assassination attempt by his rivals. Khan, ousted as prime minister in a parliamentary confidence vote in April, was six days into a protest procession bound for Islamabad, standing and waving to thousands of cheering supporters from the roof of a container truck, when the shots rang out. Several in his convoy were wounded …