its a Gemorrah
one is allowed (i believe Tosafos says it is a Mitzvah) to lie for purposes of darchei Shalom. i forget where this Gemorah is but i believe a Tosfos in Eilu Metzius (dibur hamaschiel Ushpizia on about daf 23b) references it as a kasha to the Gemorrah here that says a Talmid Chochom is allowed to lie about only 3 things.