resp-app: don't replace already present patches in rdbtools override

let

  rdbtools-patched = rdbtools.overridePythonAttrs (oldAttrs: {

    # Add required additional flag for resp-app

    patches = [

    patches = oldAttrs.patches or [ ] ++ [

      (fetchpatch {

        name = "Add-flag-to-parse-only-key-names.patch";

        url = "https://github.com/uglide/redis-rdb-tools/commit/b74946e6fbca589947ef0186429d5ce45a074b87.patch";