On --disable-openssl, the bundled neon library
will link against GNUTLS + gcrypt instead of
OpenSSL.

Change-Id: I5b3f09cd1003aefde0478aaab026536c962212c4
Reviewed-on: https://gerrit.libreoffice.org/3330Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>