Use render_if_exists for group settings page to keep same code as EE

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/views/groups/settings/_general.html.haml

@@ -19,6 +19,8 @@
         %span.light (optional)
       = f.text_area :description, class: 'form-control', rows: 3, maxlength: 250
 
+    = render_if_exists 'shared/repository_size_limit_setting', form: f, type: :group
+
     .form-group.row
       .col-sm-12
         .avatar-container.s160

app/views/groups/settings/_permissions.html.haml

@@ -23,4 +23,6 @@
 
     = render 'group_admin_settings', f: f
 
+    = render_if_exists 'member_lock_setting', f: f, group: @group
+
   = f.submit 'Save group', class: 'btn btn-success'