Fixed not-found error if using a mount-path for the Spree engine.

app/controllers/spree/static_content_controller.rb

@@ -5,7 +5,7 @@ class Spree::StaticContentController < Spree::StoreController
   layout :determine_layout
 
   def show
-    @page = Spree::Page.by_store(current_store).visible.find_by_slug!(request.path)
+    @page = Spree::Page.by_store(current_store).visible.find_by_slug!(::StaticPage.remove_spree_mount_point_if_exists(request.path))
   end
 
   private

lib/spree_static_content.rb

@@ -8,11 +8,20 @@ def self.remove_spree_mount_point(path)
     regex = Regexp.new '\A' + Rails.application.routes.url_helpers.spree_path
     path.sub( regex, '').split('?')[0]
   end
+
+  def self.remove_spree_mount_point_if_exists(path)
+    spree_path = Rails.application.routes.url_helpers.spree_path
+    if spree_path == "/"
+      return path
+    else
+      return remove_spree_mount_point(path)
+    end
+  end
 end
 
 class Spree::StaticPage
   def self.matches?(request)
     return false if request.path =~ /(^\/+(admin|account|cart|checkout|content|login|pg\/|orders|products|s\/|session|signup|shipments|states|t\/|tax_categories|user)+)/
-    !Spree::Page.visible.find_by_slug(request.path).nil?
+    !Spree::Page.visible.find_by_slug(::StaticPage.remove_spree_mount_point_if_exists(request.path)).nil?
   end
 end