ATHENS (Reuters) - Talks on a cash-for-reforms deal with Greece can resume at any time, France's Finance Minister Michel Sapin said on Monday, warning that Greece's euro membership was at stake. Sapin told France Inter radio the question for Greece was the following: "Do you want to continue the negotiations or do you want to take the risk of exiting the euro?" Of a euro exit for Greece, he said: "It’s always a possibility, it’s a risk. ...