Remove unused EVP_PKEY_ASN1_METHODs and flags.

The only alias, EVP_PKEY_RSA2, is handled programmatically. ASN1_PKEY_ALIAS and
ASN1_PKEY_DYNAMIC are then unused and unexported and can be removed.

Change-Id: I990650636bac3b802c8b439257c67ce7a3f8bc70
Reviewed-on: https://boringssl-review.googlesource.com/2124
Reviewed-by: Adam Langley <agl@google.com>

crypto/evp/internal.h

@@ -65,13 +65,11 @@ extern "C" {
 
 
 /* These values are flags for EVP_PKEY_ASN1_METHOD.flags. */
-#define ASN1_PKEY_ALIAS 0x1
-#define ASN1_PKEY_DYNAMIC 0x2
 
 /* ASN1_PKEY_SIGPARAM_NULL controls whether the default behavior of
  * EVP_DigestSignAlgorithm writes an explicit NULL parameter in the
  * AlgorithmIdentifier. */
-#define ASN1_PKEY_SIGPARAM_NULL 0x4
+#define ASN1_PKEY_SIGPARAM_NULL 0x1
 
 /* evp_digest_sign_algorithm_result_t is the return value of the
  * digest_sign_algorithm function in EVP_PKEY_ASN1_METHOD. */

crypto/evp/p_rsa_asn1.c

@@ -717,9 +717,3 @@ const EVP_PKEY_ASN1_METHOD rsa_asn1_meth = {
   rsa_digest_verify_init_from_algorithm,
   rsa_digest_sign_algorithm,
 };
-
-const EVP_PKEY_ASN1_METHOD rsa_asn1_meth_2 = {
-  EVP_PKEY_RSA2,
-  EVP_PKEY_RSA,
-  ASN1_PKEY_ALIAS,
-};