Remove unused SSL_want_* macros.

Callers doing more interesting things than read and write tend to use
SSL_get_error. SSL_want_{read,write} are still used, however.

Change-Id: I21e83cc8046742857051f755868d86deffd23d81
Reviewed-on: https://boringssl-review.googlesource.com/12688
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/ssl.h

@@ -3483,16 +3483,8 @@ OPENSSL_EXPORT int (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx))(
  * operation on |ssl| was blocked on. Use |SSL_get_error| instead. */
 OPENSSL_EXPORT int SSL_want(const SSL *ssl);
 
-#define SSL_want_nothing(ssl) (SSL_want(ssl) == SSL_NOTHING)
 #define SSL_want_read(ssl) (SSL_want(ssl) == SSL_READING)
 #define SSL_want_write(ssl) (SSL_want(ssl) == SSL_WRITING)
-#define SSL_want_x509_lookup(ssl) (SSL_want(ssl) == SSL_X509_LOOKUP)
-#define SSL_want_channel_id_lookup(ssl) (SSL_want(ssl) == SSL_CHANNEL_ID_LOOKUP)
-#define SSL_want_session(ssl) (SSL_want(ssl) == SSL_PENDING_SESSION)
-#define SSL_want_certificate(ssl) \
-  (SSL_want(ssl) == SSL_CERTIFICATE_SELECTION_PENDING)
-#define SSL_want_private_key_operation(ssl) \
-  (SSL_want(ssl) == SSL_PRIVATE_KEY_OPERATION)
 
  /* SSL_get_finished writes up to |count| bytes of the Finished message sent by
   * |ssl| to |buf|. It returns the total untruncated length or zero if none has