Support for OpenSSL 1.1.0:

- use SSL_peek instead of looping with
  has_buffered_data().

This fixes t/security/CVE-2009-3555.t where
has_buffered_data() doesn't help, because it
finds the buffered data and doesn't call
SSL_read(), so the reneg handshake isn't
triggered. SSL_peek() for 0 bytes seems to
reliably trigger the reneg in every case.

No more polling/sleeping. The code for the
OpenSSL 1.1.0 case is now again very close to
the pre 1.1.0 case.

Still need to run the full test suite with a
clean build.

Backport of r1730316 from trunk.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-openssl-1.1.0-compat@1755838 13f79535-47bb-0310-9956-ffa450edef68