Dont use avatars for user select if avatar is disabled

app/assets/javascripts/users_select.js.coffee

@@ -2,10 +2,12 @@ $ ->
   userFormatResult = (user) ->
     if user.avatar
       avatar = user.avatar.url
-    else
+    else if gon.gravatar_enabled
       avatar = gon.gravatar_url
       avatar = avatar.replace('%{hash}', md5(user.email))
       avatar = avatar.replace('%{size}', '24')
+    else
+      avatar = gon.relative_url_root + "/assets/no_avatar.png"
 
     "<div class='user-result'>
        <div class='user-image'><img class='avatar s24' src='#{avatar}'></div>

app/controllers/application_controller.rb

@@ -171,6 +171,7 @@ class ApplicationController < ActionController::Base
     gon.api_token = current_user.private_token if current_user
     gon.gravatar_url = request.ssl? || Gitlab.config.gitlab.https ? Gitlab.config.gravatar.ssl_url : Gitlab.config.gravatar.plain_url
     gon.relative_url_root = Gitlab.config.gitlab.relative_url_root
+    gon.gravatar_enabled = Gitlab.config.gravatar.enabled
   end
 
   def check_password_expiration