cve-update-db-native: show IP on failure

We get random SSL failures when fetching the CVE database, and it's
notable that the NVD server is behind a DNS round-robin or geographically
diverse servers.

On a hunch that there is one misconfigured server, dump the IP that we
connected to.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>