downloader.rb: get rid of symlinks in dist files

* tool/downloader.rb: download to the target file directly if
  CACHE_SAVE=no, to get rid of symlinks in dist files.
  [ruby-core:81887] [Bug #13709]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59292 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/downloader.rb

@@ -185,7 +185,7 @@ class Downloader
       raise
     end
     mtime = nil
-    dest = (cache && !cache.exist? ? cache : file)
+    dest = (cache_save && cache && !cache.exist? ? cache : file)
     dest.parent.mkpath
     dest.open("wb", 0600) do |f|
       f.write(data)