Link Gerrit lib into the site

Change-Id: Iffaa975245fa29f9fe48553433fa36f8439fdecd
diff --git a/gerrit@3.11.0.rb b/gerrit@3.11.0.rb
index d0b8a95..65c398f 100644
--- a/gerrit@3.11.0.rb
+++ b/gerrit@3.11.0.rb
@@ -25,6 +25,7 @@
     (var/"gerrit"/"etc").install "etc/gerrit.config"
 
     (var/"gerrit").install_symlink prefix/"plugins"
+    (var/"gerrit").install_symlink lib
 
     system "java", "-jar", bin/"gerrit.war", "init", "-d", (var/"gerrit"), "--batch", "--install-all-plugins"
   end