Remove SSL_get_(shared_)sigalgs.

These are new as of 1.0.2, not terribly useful of APIs, and are the only
reason we have to retain so many NIDs in the TLS_SIGALGS structure.

Change-Id: I7237becca09acc2ec2be441ca17364f062253893
Reviewed-on: https://boringssl-review.googlesource.com/5347
Reviewed-by: Adam Langley <agl@google.com>
2 files changed