Remove some unnecessary return values.

I'm not sure why the SSL versions of these functions return int while
the SSL_CTX version returns void. It looks like this dates to
https://boringssl-review.googlesource.com/c/1491/, of which the initial
upload was an SSL_ctrl macro. I guess one of the ints got accidentally
preserved in conversion.

(No existing caller, aside from bssl_shim, checks the result.)

Change-Id: Id54309c1aa03462d520b9a45cdfdefdd2cdd1298
Reviewed-on: https://boringssl-review.googlesource.com/13866
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

ssl/ssl_lib.c

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 5ba8256..9195905 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1567,18 +1567,16 @@
   ctx->signed_cert_timestamps_enabled = 1;
 }
 
-int SSL_enable_signed_cert_timestamps(SSL *ssl) {
+void SSL_enable_signed_cert_timestamps(SSL *ssl) {
   ssl->signed_cert_timestamps_enabled = 1;
-  return 1;
 }
 
 void SSL_CTX_enable_ocsp_stapling(SSL_CTX *ctx) {
   ctx->ocsp_stapling_enabled = 1;
 }
 
-int SSL_enable_ocsp_stapling(SSL *ssl) {
+void SSL_enable_ocsp_stapling(SSL *ssl) {
   ssl->ocsp_stapling_enabled = 1;
-  return 1;
 }
 
 void SSL_get0_signed_cert_timestamp_list(const SSL *ssl, const uint8_t **out,