Use already defined Encoding constants rather than creating one-trip Strings

actionpack/lib/action_view/template/error.rb

@@ -17,7 +17,7 @@ def initialize(string, encoding)
     end
 
     def message
-      @string.force_encoding("BINARY")
+      @string.force_encoding(Encoding::ASCII_8BIT)
       "Your template was not saved as valid #{@encoding}. Please " \
       "either specify #{@encoding} as the encoding for your template " \
       "in your text editor, or mark the template with its " \

actionpack/lib/action_view/template/handlers/erb.rb

@@ -81,7 +81,7 @@ def call(template)
           # wrong, we can still find an encoding tag
           # (<%# encoding %>) inside the String using a regular
           # expression
-          template_source = template.source.dup.force_encoding("BINARY")
+          template_source = template.source.dup.force_encoding(Encoding::ASCII_8BIT)
 
           erb = template_source.gsub(ENCODING_TAG, '')
           encoding = $2

activesupport/lib/active_support/cache/mem_cache_store.rb

@@ -158,7 +158,7 @@ def delete_entry(key, options) # :nodoc:
         # characters properly.
         def escape_key(key)
           key = key.to_s.dup
-          key = key.force_encoding("BINARY")
+          key = key.force_encoding(Encoding::ASCII_8BIT)
           key = key.gsub(ESCAPE_KEY_CHARS){ |match| "%#{match.getbyte(0).to_s(16).upcase}" }
           key = "#{key[0, 213]}:md5:#{Digest::MD5.hexdigest(key)}" if key.size > 250
           key