Drop null-auth suites from our default TLS cipher list

Previously we disallowed anonymous Diffie-Hellman, but there are other
kinds of null-authentication TLS suites.  In particular, disallowing
AECDH is important now that we support elliptic-curve Diffie-Hellman.
Reword the websocket TLS cipher list

This generates an identical list of cipher suites, but this commit
restates the cipher spec to be more similar to the way we state it
elsewhere.