elixir: 1.2.5 -> 1.2.6

[couchemar]

Motivation for this change

Update elixir version.

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

Also ejabberd-deps outputHash is updated.

I'm not an ejabberd user, so i interested in reasons why ejabberd with elixir is marked as broken? (cc @abbradar)

[mention-bot]

By analyzing the blame information on this pull request, we identified @zimbatm, @dezgeg and @abbradar to be potential reviewers

[abbradar]

I think there were compilation errors but I don't quite remember. It's not nice that change in elixir provokes a change in this hash, I'll look into it later.

[zimbatm]

output path ‘/nix/store/5hyiq0gm437day6dfb8dbdknbwd7ysg3-ejabberd-deps-16.04’ has r:sha256 hash ‘1p6qx15asmgixsdysaidcc5vyw73qp6pd5g9pl66dkkzgvgq9nxa’ when ‘0jrxd3v6p35wjrpw0jbb6m8nrm2lffhfgdcqmzcvsvjzji7nlkzx’ was expected

[abbradar]

Ouch... this likely shows that ejabberd-deps is not deterministic. I'll try to look into this later, but don't have time right now. Completely not this package's fault, though.

[zimbatm]

Right, the rest of the dependencies (hex2nix and elixir) built fine