ocaml-ipaddr: add version (2.6.1) to the system

pkgs/development/ocaml-modules/ocsigen-server/default.nix

@@ -1,17 +1,17 @@
 {stdenv, fetchurl, ocaml, findlib, which, ocaml_react, ocaml_ssl,
-ocaml_lwt, ocamlnet, ocaml_pcre, cryptokit, tyxml, ocaml_ipaddr, zlib,
+ocaml_lwt, ocamlnet, ocaml_pcre, cryptokit, tyxml, ipaddr, zlib,
 libev, openssl, ocaml_sqlite3, tree, uutf}:
 
 stdenv.mkDerivation {
   name = "ocsigenserver-2.5";
-  
+
   src = fetchurl {
     url = https://github.com/ocsigen/ocsigenserver/archive/2.5.tar.gz;
     sha256 = "0ayzlzjwg199va4sclsldlcp0dnwdj45ahhg9ckb51m28c2pw46r";
   };
 
   buildInputs = [ocaml which findlib ocaml_react ocaml_ssl ocaml_lwt
-  ocamlnet ocaml_pcre cryptokit tyxml ocaml_ipaddr zlib libev openssl
+  ocamlnet ocaml_pcre cryptokit tyxml ipaddr zlib libev openssl
   ocaml_sqlite3 tree uutf];
 
   configureFlags = "--root $(out) --prefix /";
@@ -20,7 +20,7 @@ stdenv.mkDerivation {
 
   createFindlibDestdir = true;
 
-  postFixup = 
+  postFixup =
   ''
   rm -rf $out/var/run
   '';