Pass ssh key

Dependencies

• [2] 5AIYUMTB Basic remote building
• [3] 6TY4LNHH Finish copyClosure

Change contents

• replacement in src/hydra-queue-runner/build-remote.cc at line 42
  [2.917]→[2.917:1010](∅→∅)
  − Strings argv({"ssh", "-x", "-a", sshName, "--", "nix-store", "--serve", "--write"});
  [2.917]

  [2.1010]
  + Strings argv({"ssh", sshName, "-i", sshKey, "-x", "-a", "--", "nix-store", "--serve", "--write"});