gnupg: 2.1.22 -> 2.1.23

This release in a RC for gnupg-2.2. The main difference as far as
nixpkgs is concerned is that the binary `gpg2` is now called `gpg` and
`gpgv2` is called `gpgv`.

This update fixed all explicit use of `gpg2` and `gpgv2` across nixpkgs,
but there might be some packaged software that internally use `gpg2`
not handeled by this commit.

See http://lists.gnu.org/archive/html/info-gnu/2017-08/msg00001.html
for full release information

pkgs/tools/security/pius/default.nix

@@ -13,7 +13,7 @@ stdenv.mkDerivation {
   buildInputs = [ python ];
 
   patchPhase = ''
-    sed -i "pius" -e's|/usr/bin/gpg|${gnupg}/bin/gpg2|g'
+    sed -i "pius" -e's|/usr/bin/gpg|${gnupg}/bin/gpg|g'
   '';
 
   dontBuild = true;