flow: Broken on i686

http://hydra.nixos.org/build/39411311

````
hh_shared.c:142:6: error: #error "hh_shared.c requires a architecture that supports memfd_create"
````

Changed files
+1 -1
pkgs
development
tools
analysis
+1 -1
pkgs/development/tools/analysis/flow/default.nix
···
description = "A static type checker for JavaScript";
homepage = http://flowtype.org;
license = licenses.bsd3;
-
platforms = platforms.unix;
+
platforms = [ "x86_64-linux" "x86_64-darwin" ];
maintainers = with maintainers; [ puffnfresh globin ];
};
}