Rework some bits of the networking code.

Rework some bits of the networking code.

 o Rename TLSINIT to NOSSL
 o Rename read_remote_command to read_remote.  Replace the remote read method
   with code from femail.c written by Henning Brauer of OpenBSD and licensed
   under a BSD license.  Return the first figure of the return code and check
   the appropriate values.
 o Read the server greeting at first and send EHLO afterwards.
 o Remove check_for_smtp_error().  It is included in read_remote().

This commit fixes some of the issues in issue953.  More code to come.

Dragonfly-bug: http://bugs.dragonflybsd.org/issue953