fix gravatar settings

lib/models/user.js

@@ -581,7 +581,6 @@ module.exports = function(crowi) {
 
           newUser.email = email;
           newUser.setPassword(password);
-          newUser.isGravatarEnabled = true;   // Gravatar enabled in default
           newUser.createdAt = Date.now();
           newUser.status = STATUS_INVITED;
 
@@ -658,7 +657,6 @@ module.exports = function(crowi) {
     newUser.email = email;
     newUser.setPassword(password);
     newUser.lang = lang;
-    newUser.isGravatarEnabled = false;
     newUser.createdAt = Date.now();
     newUser.status = decideUserStatusOnRegistration();