stream-ssl: Set SSL session cache mode to disables.

stream-ssl: Set SSL session cache mode to disables.

To enable SSL clients to reconnect with the ovs-testcontoller without being
rejected, one must either set the SSL Session ID flag or disable the
SSL caching. This patch disables the SSL caching/reuse.

In the absence of this fix, the error message from ovs-testcontroller is as
below:

  SSL protocol error: SSL_accept (error:140D9115:SSL
  routines:SSL_GET_PREV_SESSION:session id context uninitialized)

See <https://www.openssl.org/docs/ssl/SSL_CTX_set_session_id_context.html>.

Validation: Tested with ovs-testcontroller, by performing SSL reconnection
with OpenSSL based SSL client.

Signed-off-by: Guru Chaitanya Perakam <gperakam@brocade.com>
Reported-by: Guru Chaitanya Perakam <gperakam@brocade.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>