create: pull requires out of method

Library/Homebrew/cmd/create.rb

@@ -1,5 +1,7 @@
 require 'formula'
 require 'blacklist'
+require 'digest'
+require 'erb'
 
 module Homebrew extend self
 
@@ -96,9 +98,6 @@ class FormulaCreator
   def generate!
     raise "#{path} already exists" if path.exist?
 
-    require 'digest'
-    require 'erb'
-
     if version.nil?
       opoo "Version cannot be determined from URL."
       puts "You'll need to add an explicit 'version' to the formula."