BUENOS AIRES, June 24 : Moved by Lionel Messi's record-breaking form at the World Cup, Argentines have taken to the streets and social media to sing "Happy Birthday" to their favourite footballer who turned 39 on Wednesday. Under the hashtag #CumpleLEO, Telefé, a local television channel, launched a campaign for Argentines to sing "Happy Birthday" to him at 10 a.m. and 10 p.m. local time, an allusion to the number 10 shirt worn by the Argentina captain. Waving Argentine flags, groups of friends