exodus: fix the desktop file patch

Escapes for ` and a %u have been added in upstream .desktop file, breaking the
patch in the derivation.

pkgs/applications/blockchains/exodus/default.nix

@@ -24,7 +24,7 @@ stdenv.mkDerivation rec {
     ln -s $out/bin/Exodus $out/bin/exodus
     ln -s $out/exodus.desktop $out/share/applications
     substituteInPlace $out/share/applications/exodus.desktop \
-          --replace 'Exec=bash -c "cd `dirname %k` && ./Exodus"' "Exec=Exodus"
+          --replace 'Exec=bash -c "cd \`dirname %k\` && ./Exodus %u"' "Exec=Exodus %u"
   '';
 
   dontPatchELF = true;