Address various encryption related CVEs and RFCs

Openflow plugin uses TLS without restricting the cipher list to eliminate various ciphers which have been found vulnerable:

RC4 - RFC 7465
Export ciphers - LOGJAM: TLS connections which support export grade DHE key-exchange are vulnerable to MITM attacks CVE-2015-4000

This is presently being worked on the controller project as bugs 3351, 3352, 3353.

3352 should provide the relevant configuration mechanisms and utility classes for other projects to use to configure ciphers for native (not http) tls correctly.