simple_form: regen config files (#2913).

Regens simple form config using `rails generate simple_form:install`.
Seems to fix #2913 (erroneous minlength validations being enforced as of
simple_form 3.4.0).

lib/templates/erb/scaffold/_form.html.erb

@@ -1,23 +1,13 @@
-<%%= simple_form_for(@<%= singular_name %>) do |f| %>
-  <%% if @<%= singular_name %>.errors.any? %>
-    <div id="error_explanation">
-      <h2><%%= pluralize(@<%= singular_name %>.errors.count, "error") %> prohibited this <%= singular_name %> from being saved:</h2>
+<%%= simple_form_for(@<%= singular_table_name %>) do |f| %>
+  <%%= f.error_notification %>
 
-      <ul>
-      <%% @<%= singular_name %>.errors.full_messages.each do |msg| %>
-        <li><%%= msg %></li>
-      <%% end %>
-      </ul>
-    </div>
-  <%% end %>
-
-  <div class="inputs">
+  <div class="form-inputs">
   <%- attributes.each do |attribute| -%>
     <%%= f.<%= attribute.reference? ? :association : :input %> :<%= attribute.name %> %>
   <%- end -%>
   </div>
 
-  <div class="actions">
+  <div class="form-actions">
     <%%= f.button :submit %>
   </div>
 <%% end %>