Remove unused variable

Library/Homebrew/build.rb

@@ -140,7 +140,7 @@ class Build
 
     if f.fails_with? ENV.compiler
       begin
-        ENV.send CompilerSelector.new(f, ENV.compiler).compiler
+        ENV.send CompilerSelector.new(f).compiler
       rescue CompilerSelectionError => e
         raise e.message
       end

Library/Homebrew/compilers.rb

@@ -35,9 +35,8 @@ class CompilerQueue
 end
 
 class CompilerSelector
-  def initialize(f, old_compiler)
+  def initialize(f)
     @f = f
-    @old_compiler = old_compiler
     @compilers = CompilerQueue.new
     %w{clang llvm gcc gcc_4_0}.map(&:to_sym).each do |cc|
       unless MacOS.send("#{cc}_build_version").nil?

Library/Homebrew/test/test_compiler_selector.rb

@@ -27,7 +27,7 @@ class CompilerSelectorTests < Test::Unit::TestCase
   end
 
   def actual_cc
-    CompilerSelector.new(@f, @cc).compiler
+    CompilerSelector.new(@f).compiler
   end
 
   def test_all_compiler_failures