diff --git a/Library/Homebrew/extend/ENV/super.rb b/Library/Homebrew/extend/ENV/super.rb
index 57d07c637b..1afc94a0db 100644
--- a/Library/Homebrew/extend/ENV/super.rb
+++ b/Library/Homebrew/extend/ENV/super.rb
@@ -28,6 +28,7 @@ module Superenv
     # done on the singleton class, because in MRI all ENV methods are defined
     # on its singleton class, precluding the use of extend.
     class << base
+      alias_method :"old_[]", :[]
       def [] key
         if has_key? key
           fetch(key)
diff --git a/Library/Homebrew/software_spec.rb b/Library/Homebrew/software_spec.rb
index 010d4ef839..1811115406 100644
--- a/Library/Homebrew/software_spec.rb
+++ b/Library/Homebrew/software_spec.rb
@@ -97,6 +97,7 @@ class Bottle < SoftwareSpec
     @revision = 0
     @prefix = '/usr/local'
     @cellar = '/usr/local/Cellar'
+    @root_url = nil
   end
 
   # Checksum methods in the DSL's bottle block optionally take