Fix libinet version detection

Library/Homebrew/extend/pathname.rb

@@ -117,6 +117,10 @@ class Pathname
     %r[github.com/.*/(zip|tar)ball/v?((\d\.)+\d+)$].match to_s
     return $2 if $2
 
+    # eg. https://github.com/sam-github/libnet/tarball/libnet-1.1.4
+    %r[github.com/.*/(zip|tar)ball/.*-((\d\.)+\d+)$].match to_s
+    return $2 if $2
+
     # dashed version
     # eg. github.com/isaacs/npm/tarball/v0.2.5-1
     %r[github.com/.*/(zip|tar)ball/v?((\d\.)+\d+-(\d+))$].match to_s

Library/Homebrew/test/test_versions.rb

@@ -61,6 +61,10 @@ class VersionTests < Test::Unit::TestCase
       '9.04'
   end
 
+  def test_new_github_style
+    check "https://github.com/sam-github/libnet/tarball/libnet-1.1.4", "1.1.4"
+  end
+
   def test_gloox_beta_style
     check "http://camaya.net/download/gloox-1.0-beta7.tar.bz2", '1.0-beta7'
   end