chore(3p/glog): Unvendor glog

... and build //third_party/nix with the one from nixpkgs.

Change-Id: Iae7f1772a31286f2c22955cdc1fe61ee82d112aa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3016
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: grfn <grfn@gws.fyi>

third_party/nix/default.nix

@@ -85,15 +85,15 @@ lib.fix (self: pkgs.fullLlvm11Stdenv.mkDerivation {
     curl
     editline
     flex
+    glog
     libseccomp
     libsodium
-    systemd.dev
     openssl
     sqlite
+    systemd.dev
     xz
   ]) ++ (with depot.third_party; [
     abseil_cpp
-    glog
     grpc
     protobuf
   ]);