Don't wait for banner message from SMTP server after STARTTLS negotiation

According to RFC 2847 section 5.2, SMTP server won't send banner message
again after STARTTLS negotiation. The original code will hang until
SMTP server kicks it off due to timeout and can't send email with
STARTTLS enabled, aka. sendemail.smtpEncryption = tls.

Bug: Issue 1397
Change-Id: I5822e7f1aae0e13ea082964702bde96132f73e2c
1 file changed