tls: Re-enable check of CN-ID in cert verification

RFC 6125 explicitly states that a client "MUST NOT seek a match
for a reference identifier of CN-ID if the presented identifiers
include a DNS-ID, SRV-ID, URI-ID, or any application-specific
identifier types supported by the client", but it MAY do so if
none of the mentioned identifier types (but others) are present.
Merge branch 'v0.8' into v0.8-httpp
Merge branch 'v0.8-httpp' of https://github.com/InstantWebP2P/node-httpp into v0.8-httpp