PR: 1794

Submitted by: Peter Sylvester <peter.sylvester@edelweb.fr>
Reviewed by: steve

Make SRP conformant to rfc 5054.

Changes are:

- removal of the addition state after client hello
- removal of all pre-rfc srp alert ids
- sending a fatal alert when there is no srp extension but when the
server wants SRP
- removal of unnecessary code in the client.