MADRID, July 9 (Reuters) - Belgium's prime minister was a little surprised on landing back home from Wednesday's NATO summit in Turkey to find that he had a handgun and ammunition in his luggage. After NATO leaders gathered for Wednesday's fractious summit in Ankara, their host, Turkish President Recep Tayyip Erdogan, handed each an unusual parting gift: a vintage revolver, along with live ammunition indicating it was not just for show. Erdogan wanted to showcase Turkey's defence industry, which