(r)rsync: simplify and don't copy maintainers

Let's keep the original rsync maintainers only on rsync,
as I haven't noticed them wanting to maintain rrsync as well.

pkgs/applications/networking/sync/rsync/base.nix

···
 { stdenv, fetchurl }:
 
-let
+rec {
   version = "3.2.1";
-in
-{
-  version = version;
   src = fetchurl {
     # signed with key 0048 C8B0 26D4 C96F 0E58  9C2F 6C85 9FB1 4B96 A8C5
     url = "mirror://samba/rsync/src/rsync-${version}.tar.gz";
···
 
   meta = with stdenv.lib; {
     homepage = http://rsync.samba.org/;
-    #description = "A helper to run rsync-only environments from ssh-logins.";
     license = licenses.gpl3Plus;
     platforms = platforms.unix;
-    maintainers = with maintainers; [ simons ehmry kampfschlaefer ];
   };
-}
+}

pkgs/applications/networking/sync/rsync/default.nix

···
 
   meta = base.meta // {
     description = "A fast incremental file transfer utility";
+    maintainers = with stdenv.lib.maintainers; [ simons ehmry kampfschlaefer ];
   };
 }

pkgs/applications/networking/sync/rsync/rrsync.nix

···
 
   meta = base.meta // {
     description = "A helper to run rsync-only environments from ssh-logins";
+    maintainers = [ stdenv.lib.maintainers.kampfschlaefer ];
   };
 }