cvs: use ssh instead of rsh.

If no ssh executable can be found during the configure phase, CVS
defaults to using rsh for remote connections instead.

pkgs/applications/version-management/cvs/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, fetchpatch, nano }:
+{ lib, stdenv, fetchurl, fetchpatch, nano, runCommand }:
 
 stdenv.mkDerivation rec {
  pname = "cvs";
@@ -9,6 +9,14 @@ stdenv.mkDerivation rec {
  sha256 = "0pjir8cwn0087mxszzbsi1gyfc6373vif96cw4q3m1x6p49kd1bq";
  };
 
+ fake-ssh = runCommand "fakeSsh" {} ''
+ mkdir -p $out/bin
+ touch $out/bin/ssh
+ chmod +x $out/bin/ssh
+ '';
+
+ buildInputs = [fake-ssh];
+
  patches = [
  ./getcwd-chroot.patch
  ./CVE-2012-0804.patch