Add version attribute where maintainers |= nckx

This will probably be mandatory soon, and is a step in the right
direction. Removes the deprecated meta.version, and move some meta
sections to the end of the file where I should have put them in
the first place.

pkgs/tools/networking/pingtcp/default.nix

@@ -1,8 +1,8 @@
 { stdenv, fetchgit, cmake }:
 
-let version = "0.0.3"; in
-stdenv.mkDerivation {
+stdenv.mkDerivation rec {
   name = "pingtcp-${version}";
+  version = "0.0.3";
 
   # This project uses git submodules, which fetchFromGitHub doesn't support:
   src = fetchgit {
@@ -27,7 +27,6 @@ stdenv.mkDerivation {
   '';
 
   meta = with stdenv.lib; {
-    inherit version;
     description = "Measure TCP handshake time";
     homepage = https://github.com/LanetNetwork/pingtcp;
     license = licenses.gpl3;