Pathname.version on directories ignores extname

Because directories don't have extensions.

Included test

Library/Homebrew/pathname+yeast.rb

@@ -87,6 +87,13 @@ class Pathname
   end
 
   def version
+    if directory?
+      # directories don't have extnames
+      stem=basename.to_s
+    else
+      stem=self.stem
+    end
+
     # github tarballs are special
     # we only support numbered tagged downloads
     %r[github.com/.*/tarball/((\d\.)+\d)$].match to_s

Library/Homebrew/unittest.rb

@@ -294,4 +294,10 @@ class BeerTasting <Test::Unit::TestCase
     assert_equal 1, ARGV.kegs.length
     assert_raises(FormulaUnavailableError) { ARGV.formulae }
   end
+  
+  def test_version_dir
+    d=HOMEBREW_CELLAR+'foo-0.1.9'
+    d.mkpath
+    assert_equal '0.1.9', d.version
+  end
 end