message: fix: Update nix dependency to git revision that exists
diff: @@ -865,7 +865,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
  [[package]]
  name = "libc"
  version = "0.2.64"
  -source = "git+https://github.com/rust-lang/libc#56850068dcb7851213bf233ceae159a0229d533d"
  +source = "git+https://github.com/rust-lang/libc#ff63cb517872d95bdba9960d4d200d024c1805a0"
  [[package]]
  name = "libloading"
  @@ -988,7 +988,7 @@ dependencies = [
  [[package]]
  name = "nix"
  version = "0.15.0"
  -source = "git+https://github.com/AdminXVII/nix?branch=add-redox-support#65a419c85be86b00ab9b694f81eeb43116620f2b"
  +source = "git+https://github.com/AdminXVII/nix?branch=add-redox-support#491397e20779381fe3366adeeec2a5540e00b926"
  dependencies = [
  "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)",
  