Use Homebrew’s `require?`.

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

@@ -91,17 +91,6 @@ module Hbc
       @lookup.fetch(command_string, command_string)
     end
 
-    # modified from Homebrew
-    def self.require?(path)
-      require path
-      true # OK if already loaded
-    rescue LoadError => e
-      # HACK: :( because we should raise on syntax errors
-      #       but not if the file doesn't exist.
-      # TODO: make robust!
-      raise unless e.to_s.include? path
-    end
-
     def self.should_init?(command)
       (command.is_a? Class) && (command < CLI::Base) && command.needs_init?
     end