What happens if you roll a 7 before the barbarians reach the island?
The English rules are correct; you still must discard half your hand if you are holding too many cards. You can find the latest edition of the rulebook on catan.com here. It says;


  The robber cannot be moved until after the barbarians reach the island of Catan for the first time. Until the first barbarian attack, if you roll a "7", each player must check if he is holding too many cards as usual; however, you do not move the robber from the desert and you do not steal a card from another player.