Add boost dependency

Dependencies

• [2] VPAUFJTI Use PostgreSQL 9.5
• [*] T4LLYESZ * Nix expression for building Hydra.
• [*] ICYJNJWH Revert "Move build logic for the core hydra package into its own default.nix."

Change contents

• edit in release.nix at line 113
  [2.103]

  [5.2651]
  + boost