Error handling bug

[Novikov Bogdan]

When user cancel auth request - server throw 5xx errors.
By design - it must redirected to failureRedirect.

[Novikov Bogdan]

See jaredhanson/passport-facebook#93
Worked example:

router.get('/auth/vk/callback',
    passport.authenticate('vk',  { failureRedirect : '/login-failed'}),

    // on succes
    function(req,res) {
        // setup succes message
        // .......
    },

    // on error
    function(err,req,res,next) {
        res.redirect('/login-failed');
    }

);

UPD for new version of passportjs see:
https://github.com/jaredhanson/passport/blob/master/lib/middleware/authenticate.js#L24