String already respond_to scrub at Ruby 2.2

Author: rafaelfranca

activesupport/lib/active_support/multibyte/unicode.rb

@@ -211,9 +211,8 @@ def compose(codepoints)
         codepoints
       end
 
-      # Ruby >= 2.1 has String#scrub, which is faster than the workaround used for < 2.1.
       # Rubinius' String#scrub, however, doesn't support ASCII-incompatible chars.
-      if '<3'.respond_to?(:scrub) && !defined?(Rubinius)
+      if !defined?(Rubinius)
         # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
         # resulting in a valid UTF-8 string.
         #