rsync: add patch for CVE-2020-14387

(cherry picked from commit a08ee2292caa8a676332c695d7d46bd38c235931)

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

@@ -1,7 +1,7 @@
-{ lib, stdenv, fetchurl, perl, rsync }:
+{ lib, stdenv, fetchurl, perl, rsync, fetchpatch }:
 
 let
-  base = import ./base.nix { inherit lib fetchurl; };
+  base = import ./base.nix { inherit lib fetchurl fetchpatch; };
 in
 stdenv.mkDerivation {
   name = "rrsync-${base.version}";
@@ -15,6 +15,8 @@ stdenv.mkDerivation {
   dontConfigure = true;
   dontBuild = true;
 
+  patches = base.extraPatches;
+
   postPatch = ''
     substituteInPlace support/rrsync --replace /usr/bin/rsync ${rsync}/bin/rsync
   '';