Fix asset_url with asset_hash (#1919)

* Fix asset_url with asset_hash.

* Fix asset hashes.

middleman-core/lib/middleman-core/util/paths.rb

@@ -118,7 +118,9 @@ module Middleman
       # relative path, since it only takes absolute url paths.
       dest_path = url_for(app, path, options.merge(relative: false))
 
-      result = if resource = app.sitemap.find_resource_by_destination_path(dest_path)
+      result = if resource = app.sitemap.find_resource_by_path(dest_path)
+        resource.url
+      elsif resource = app.sitemap.find_resource_by_destination_path(dest_path)
         resource.url
       else
         path = ::File.join(prefix, path)

middleman-core/spec/middleman-core/util_spec.rb

@@ -162,6 +162,13 @@ describe Middleman::Util do
       expect( Middleman::Util.asset_url( @mm, '/how/about/that.html' ) ).to eq '/how/about/that/'
     end
 
+    it "returns a resource url when asset_hash is on" do
+      Given.fixture 'asset-hash-app'
+      @mm = Middleman::Application.new
+
+      expect( Middleman::Util.asset_url( @mm, '100px.png', 'images') ).to match %r|/images/100px-[a-f0-9]+.png|
+    end
+
   end
 
   describe "::find_related_files" do