Recover SSL_OP_CIPHER_SERVER_PREFERENCE documentation.

b9cc33a4d6d935f71c3e70af9718e716b00712e8 deleted its documentation rather than
SSL_OP_EPHEMERAL_RSA's.

Change-Id: I2e099a2dc498f145c5a3ccaac824edbda27f7e89
Reviewed-on: https://boringssl-review.googlesource.com/2407
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/ssl.h

diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index dab8753..b5e0d8b 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -468,8 +468,8 @@
 #define SSL_OP_SINGLE_ECDH_USE				0x00080000L
 /* If set, always create a new key when using tmp_dh parameters */
 #define SSL_OP_SINGLE_DH_USE				0x00100000L
-/* Set to always use the tmp_rsa key when doing RSA operations,
- * even when this violates protocol specs */
+/* Set on servers to choose the cipher according to the server's
+ * preferences */
 #define SSL_OP_CIPHER_SERVER_PREFERENCE			0x00400000L
 /* SSL_OP_TLS_ROLLBACK_BUG does nothing. */
 #define SSL_OP_TLS_ROLLBACK_BUG				0x00800000L