Merge pull request #1264 from reitermarkus/single-language-audit

Allow auditing of a single language of a cask.

Library/Homebrew/cask/lib/hbc/auditor.rb

 module Hbc
   class Auditor
     def self.audit(cask, audit_download: false, check_token_conflicts: false)
-      if languages_blocks = cask.instance_variable_get(:@dsl).instance_variable_get(:@language_blocks)
+      if !ARGV.value("language") &&
+        languages_blocks = cask.instance_variable_get(:@dsl).instance_variable_get(:@language_blocks)
         begin
           saved_languages = MacOS.instance_variable_get(:@languages)
 
           languages_blocks.keys.map { |languages|
             ohai "Auditing language: #{languages.map { |lang| "'#{lang}'" }.join(", ")}"
             MacOS.instance_variable_set(:@languages, languages)
-            CLI::Cleanup.run(cask.token) if audit_download
             audit_cask_instance(Hbc.load(cask.sourcefile_path), audit_download, check_token_conflicts)
+            CLI::Cleanup.run(cask.token) if audit_download
           }.all?
         ensure
           MacOS.instance_variable_set(:@languages, saved_languages)