Fix VM test

Dependencies

• [2] 7C6HSXUQ * Start of a regression test for Hydra.
• [3] 3PNG7NIB Remove trailing whitespace
• [4] 5FP63F5T More command renaming.
• [*] T4LLYESZ * Nix expression for building Hydra.

Change contents

• replacement in release.nix at line 118
  [2.668]→[2.668:748](∅→∅)
  − , "psql hydra -f ${hydra}/share/hydra/sql/hydra-postgresql.sql"
  [2.668]

  [2.748]
  + , "psql hydra -f ${hydra}/libexec/hydra/sql/hydra-postgresql.sql"