gce/create-gce.sh: rewrite using nix-shell shebang and bash (#24869)

* google-cloud-sdk: 150.0.0 -> 151.0.0

- gce/create-gce.sh: rewrite using nix-shell shebang and bash
- allows to run the script without being the same directory
- nix-shell install google-cloud-sdk
- some shellcheck cleanups and scripting best practice
- gce/create-gce.sh: do not clobber NIX_PATH: this allows NIX_PATH to be overwritten to build a different release
- gce/create-gce.sh: remove legacy hydra option

pkgs/tools/admin/google-cloud-sdk/default.nix

@@ -7,23 +7,23 @@ assert stdenv.system == "i686-linux" || stdenv.system == "x86_64-linux" || stden
 
 stdenv.mkDerivation rec {
   name = "google-cloud-sdk-${version}";
-  version = "150.0.0";
+  version = "151.0.0";
 
   src =
     if stdenv.system == "i686-linux" then
       fetchurl {
         url = "https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/${name}-linux-x86.tar.gz";
-        sha256 = "0zg6jnn93dq53glds4cghksyghb4d4z0i2h38na0r88mr8hzmx1l";
+        sha256 = "1d1h6jiqs3grsb6c61v6dkb4l2qv6v8g7wbzgaqkmn09xdbaq40l";
       }
     else if stdenv.system == "x86_64-darwin" then
       fetchurl {
         url = "https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/${name}-darwin-x86_64.tar.gz";
-        sha256 = "1vbc360z2da3blwx51asw7jh0v0v6wsrv20z36yq0hccmljlh24w";
+        sha256 = "05idf0g505s8diaz28ij9yqig2wwn43lyppfs483m7vnx5hk62j5";
       }
     else
       fetchurl {
         url = "https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/${name}-linux-x86_64.tar.gz";
-        sha256 = "1q66aap3qidfsa8gm13jff3dprx8qarhjkx5ib65439fy4zj0bca";
+        sha256 = "01hf7pp1v57dxx6f2pz7j13fjdnrfp7gjmzjdlhlx4rnvxrd6i3f";
       };
 
   buildInputs = [python27 makeWrapper];