Don't lock anything in SSL_set_generate_session_id.

Nothing else on SSL* is thread-safe. (Also SSL_set_generate_session_id is never
called.) This removes the last use of CRYPTO_LOCK_SSL.

Change-Id: I4cf8c05d7cef4ea27962ce29902649317c22f74d
Reviewed-on: https://boringssl-review.googlesource.com/3361
Reviewed-by: Adam Langley <agl@google.com>
1 file changed