Fix email notification

Dependencies

• [2] 2ANV36PB Hackery
• [3] L62I7CPI Don't put ssmtp in hydra's paths
• [4] ZYEFL36Q Ported/merged properties from the TUD configuration's hydra-module
• [5] EE5RRP3X hydra-module.nix: Make services require hydra-init
• [*] D3MDJONY

Change contents

• replacement in hydra-module.nix at line 261
  [3.1588]→[3.0:34](∅→∅)
  − path = [ pkgs.nettools ];
  [3.1588]

  [2.127]
  + path = [ pkgs.nettools pkgs.ssmtp ];
• replacement in hydra-module.nix at line 279
  [3.2103]→[3.35:69](∅→∅)
  − path = [ pkgs.nettools ];
  [3.2103]

  [3.2148]
  + path = [ pkgs.nettools pkgs.ssmtp ];