hydra: add bazaar to path

Dependencies

• [2] FGI75W53 move nix-prefetch-* into tarball
• [3] YQWH4POV * Simplify.
• [4] O25D52TA initial support for mercurial
• [5] QK2OXCKP hydra/release.nix: move manual to tarball build, restore version in store path for tarball build
• [6] T4LLYESZ * Nix expression for building Hydra.

Change contents

• edit in release.nix at line 28
  [2.248]

  [3.115]
  + cp ${"${nixpkgs}/pkgs/build-support/fetchbzr/nix-prefetch-bzr"} src/script
• replacement in release.nix at line 60
  [3.2094]→[3.337:404](∅→∅)
  − gzip bzip2 lzma gnutar unzip git mercurial gnused graphviz
  [3.2094]

  [3.2159]
  + gzip bzip2 lzma gnutar unzip git mercurial gnused graphviz bazaar