LONDON — The European Commission is unlikely to reach an immediate deal on allowing third-party entry to the EU’s flagship loan program for defense, after talks between London and Brussels ran aground over financial issues.  The EU is negotiating with the U.K. and Canada over access to the EU’s €150 billion Security Action for Europe loans-for-weapons initiative, which allows EU member countries to take low interest loans and then jointly procure weapons systems. Gaining access was once