smb: use memcpy() instead of strncpy()

... as it never copies the trailing zero anyway and always just the four
bytes so let's not mislead anyone into thinking it is actually treated
as a string.

Coverity CID: 1260214
openssl: warn for SRP set if SSLv3 is used, not for TLS version

... as it requires TLS and it was was left to warn on the default from
when default was SSL...