Include a check to ensure accessToken is return

Author: Ben

lib/strategy.js

@@ -175,6 +175,7 @@ OAuth2Strategy.prototype.authenticate = function(req, options) {
       self._oauth2.getOAuthAccessToken(code, params,
         function(err, accessToken, refreshToken, params) {
           if (err) { return self.error(self._createOAuthError('Failed to obtain access token', err)); }
+          if (!accessToken){ return self._createOAuthError('Failed to obtain access token', err)}
 
           self._loadUserProfile(accessToken, function(err, profile) {
             if (err) { return self.error(err); }