Clean up some more error handling in mod_ssl:

* modules/ssl/ssl_engine_io.c (ssl_filter_io_shutdown): Remove
  redundant return value (which was always success).
  (ssl_io_filter_handshake): Return APR_ECONNABORTED on handshake
  failure, rather than success.
  (ssl_io_filter_output): Ignore ssl_filter_io_shutdown return
  value.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@645584 13f79535-47bb-0310-9956-ffa450edef68