ocamlPackages.ca-certs: disable test suite expecting nss db

nss-cacert has updated a few certificates, including Google's which
breaks the test suite of ca-certs expecting the old version.

pkgs/development/ocaml-modules/ca-certs/default.nix

···
 
   propagatedBuildInputs = [ bos fpath rresult ptime mirage-crypto x509 astring logs ];
 
-  doCheck = true;
+  # Assumes nss-cacert < 3.74 https://github.com/mirage/ca-certs/issues/21
+  doCheck = false;
   checkInputs = [
     cacert    # for /etc/ssl/certs/ca-bundle.crt
     alcotest