Revert asset alias check

[josh]

@rafaelfranca wdyt about just rolling this back? It should fix @dhh's problem in rails/sprockets#36.

[rafaelfranca]

Yeah, seems better to revert and come with a solution that will work for that case.

[dhh]

Awesome. That does the trick for me.

I can open another ticket for this, but we also hit a big performance regression upgrading. These changes:

 GIT
   remote: git://github.com/rails/sprockets-rails.git
-  revision: 0159123f01a54170f651934e1fef9b3f61341fcc
+  revision: 4844424fe71944350cb0645c2d81ac49ae6d3f36
   specs:
     sprockets-rails (3.0.0.beta1)
       actionpack (>= 4.0)
       activesupport (>= 4.0)
-      sprockets (>= 3.0.0.beta, < 4.0)
+      sprockets (>= 3.0.0, < 4.0)

 GIT
   remote: git://github.com/rails/sprockets.git
-  revision: 92eb3072790cef9f1e28c9670abeddcf45de8099
-  ref: 92eb3072790cef9f1e28c9670abeddcf45de8099
+  revision: 4e555b82cf43c0ddb0dbeda7c68bc306bc094533
   specs:
-    sprockets (3.0.0.beta.8)
+    sprockets (3.1.0)
       rack (~> 1.0)

Take our total suite run time from 54s to 72s on my machine.

[josh]

@dhh ah nice.

I had an idea for that but haven't got around to implementing it yet. I'll take another stab on the weekend.

[dhh]

Let me know if there's anything else for me to try re: the performance hit.