It can be safely ignored. I'm assuming /usr/src is empty on your system. In that case, you can remove the src entry under Components in /etc/freebsd-update.conf to prevent this from happening again. You can either do it manually or copy/paste this:
sed -i '' -e '/^Components/ s/ src//' /etc/freebsd-update.conf
If you do have source, make the path of the directory so the file can be installed when freebsd-update install runs.
mkdir -p /usr/src/crypto/openssl/util
