Check if Cellar and Cache exist before cleaning.

Library/Homebrew/cmd/cleanup.rb

@@ -7,6 +7,7 @@ module Homebrew extend self
 
   def cleanup
     if ARGV.named.empty?
+      if HOMEBREW_CELLAR.directory?
         HOMEBREW_CELLAR.children.each do |rack|
           begin
             cleanup_formula rack.basename.to_s if rack.directory?
@@ -15,6 +16,7 @@ module Homebrew extend self
             # instead of core formulae.
           end
         end
+      end
       clean_cache
       # seems like a good time to do some additional cleanup
       unless ARGV.dry_run?
@@ -54,6 +56,7 @@ module Homebrew extend self
   end
 
   def clean_cache
+    return unless HOMEBREW_CACHE.directory?
     HOMEBREW_CACHE.children.each do |pn|
       next unless pn.file?
       version = pn.version