Apply Rafaels review fixes.

railties/lib/rails/command/behavior.rb

@@ -21,7 +21,7 @@ def subclasses
           # This code is based directly on the Text gem implementation.
           # Copyright (c) 2006-2013 Paul Battley, Michael Neumann, Tim Fletcher.
           #
-          # Returns a value representing the "cost" of transforming str1 into str2
+          # Returns a value representing the "cost" of transforming str1 into str2.
           def levenshtein_distance(str1, str2)
             s = str1
             t = str2

railties/lib/rails/commands/server/server_command.rb

@@ -90,7 +90,9 @@ def middleware
     end
 
     def default_options
-      super.merge(        Port:               ENV.fetch("PORT", 3000).to_i,
+      super.merge(
+        Port:               ENV.fetch("PORT", 3000).to_i,
+        Host:               ENV.fetch("HOST", "localhost").dup,
         DoNotReverseLookup: true,
         environment:        (ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development").dup,
         daemonize:          false,

railties/lib/rails/test_unit/minitest_plugin.rb

 require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/hash/keys"
 require "rails/test_unit/reporter"
 require "rails/test_unit/test_requirer"
 require "shellwords"