Give SoftwareSpec an initializer

Tools like `brew create` need to create and manipulate SoftwareSpec
objects. It is useful to be able to do this directly, rather than by
proxy through the special methods that serve the main formula DSL.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/cmd/create.rb

@@ -88,10 +88,8 @@ class FormulaCreator
     end
 
     unless ARGV.include? "--no-fetch" and version
-      strategy = DownloadStrategyDetector.new(url).detect
-      spec = SoftwareSpec.new
-      spec.url(url)
-      spec.version(version)
+      spec = SoftwareSpec.new(url, version)
+      strategy = spec.download_strategy
       @sha1 = strategy.new(name, spec).fetch.sha1 if strategy == CurlDownloadStrategy
     end
 

Library/Homebrew/formula_support.rb

@@ -4,6 +4,11 @@ require 'checksums'
 class SoftwareSpec
   attr_reader :checksum, :mirrors, :specs
 
+  def initialize url=nil, version=nil
+    @url = url
+    @version = version
+  end
+
   # Was the version defined in the DSL, or detected from the URL?
   def explicit_version?
     @explicit_version || false
@@ -67,9 +72,8 @@ class SoftwareSpec
 end
 
 class HeadSoftwareSpec < SoftwareSpec
-  def initialize
+  def initialize url=nil, version='HEAD'
     super
-    @version = 'HEAD'
   end
 
   def verify_download_integrity fn
@@ -81,7 +85,7 @@ class Bottle < SoftwareSpec
   attr_writer :url
   attr_reader :revision
 
-  def initialize
+  def initialize url=nil, version=nil
     super
     @revision = 0
   end