trafficserver: add svn HEAD

Closes Homebrew/homebrew#10154.

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

Formula/trafficserver.rb

@@ -5,6 +5,8 @@ class Trafficserver < Formula
   homepage 'http://trafficserver.apache.org/'
   md5 '0f8e5ce658d28511001c6585d1e1813a'
 
+  head 'http://svn.apache.org/repos/asf/trafficserver/traffic/trunk/'
+
   devel do
     url 'http://www.apache.org/dyn/closer.cgi/trafficserver/trafficserver-3.1.2-unstable.tar.bz2'
     md5 '2208cb9a0d0b7cea07770d51b1cf7df2'
@@ -14,6 +16,8 @@ class Trafficserver < Formula
   depends_on 'pcre'
 
   def install
+    system "autoreconf -i" if ARGV.build_head?
+
     # Needed for correct ./configure detections.
     ENV.enable_warnings
     # Needed for OpenSSL headers on Lion.