sslutil: abort if peer certificate is not verified for secure use Before this patch, "sslutil.validator" may returns successfully, even if peer certificate is not verified because there is no information in "[hostfingerprints]" and "[web] cacerts". To prevent from sending authentication credential to untrustable SMTP server, validation should be aborted if peer certificate is not verified. This patch introduces "strict" optional argument, and "sslutil.validator" will abort if it is True and peer certificate is not verified.