Check certificate extensions in trusted certificates.

Check certificate extensions in trusted certificates.

Historically the standards let the implementation decide to
either check or ignore the certificate properties of trust anchors.
You could either use them simply as a source of a public key which
was trusted for everything, or you were also permitted to check the
certificate properties and fully enforce them. Hooray for freedumb.

OpenSSL changed to checking these with :
commit 0daccd4dc1f1ac62181738a91714f35472e50f3c
Author: Viktor Dukhovni <openssl-users@dukhovni.org>
Date:   Thu Jan 28 03:01:45 2016 -0500

BoringSSL currently does not check them, as it also inherited
the previous OpenSSL behaviour. It will change to check them in
the future.
(https://bugs.chromium.org/p/boringssl/issues/detail?id=533)