Prune removed key types from SSL_PKEY_*.

Remove all the logic managing key types that aren't being used anymore.

Change-Id: I101369164588048e64ba1c84a6b8aac8f3a221cd
Reviewed-on: https://boringssl-review.googlesource.com/1567
Reviewed-by: Adam Langley <agl@google.com>
6 files changed