Rename the BIGNUM ASN.1 functions.

There's many ways to serialize a BIGNUM, so not including asn1 in the name is
confusing (and collides with BN_bn2cbb_padded). Since BN_asn12bn looks
ridiculous, match the parse/marshal naming scheme of other modules instead.

Change-Id: I53d22ae0537a98e223ed943e943c48cb0743cf51
Reviewed-on: https://boringssl-review.googlesource.com/6822
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/include/openssl/bn.h b/include/openssl/bn.h
index 6e971e4..64ec5c9 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -303,17 +303,17 @@
 
 /* ASN.1 functions. */
 
-/* BN_cbs2unsigned parses a non-negative DER INTEGER from |cbs| writes the
- * result to |ret|. It returns one on success and zero on failure. */
-OPENSSL_EXPORT int BN_cbs2unsigned(CBS *cbs, BIGNUM *ret);
+/* BN_parse_asn1_unsigned parses a non-negative DER INTEGER from |cbs| writes
+ * the result to |ret|. It returns one on success and zero on failure. */
+OPENSSL_EXPORT int BN_parse_asn1_unsigned(CBS *cbs, BIGNUM *ret);
 
-/* BN_cbs2unsigned_buggy acts like |BN_cbs2unsigned| but tolerates some invalid
- * encodings. Do not use this function. */
-OPENSSL_EXPORT int BN_cbs2unsigned_buggy(CBS *cbs, BIGNUM *ret);
+/* BN_parse_asn1_unsigned_buggy acts like |BN_parse_asn1_unsigned| but tolerates
+ * some invalid encodings. Do not use this function. */
+OPENSSL_EXPORT int BN_parse_asn1_unsigned_buggy(CBS *cbs, BIGNUM *ret);
 
-/* BN_bn2cbb marshals |bn| as a non-negative DER INTEGER and appends the result
- * to |cbb|. It returns one on success and zero on failure. */
-OPENSSL_EXPORT int BN_bn2cbb(CBB *cbb, const BIGNUM *bn);
+/* BN_marshal_asn1 marshals |bn| as a non-negative DER INTEGER and appends the
+ * result to |cbb|. It returns one on success and zero on failure. */
+OPENSSL_EXPORT int BN_marshal_asn1(CBB *cbb, const BIGNUM *bn);
 
 
 /* Internal functions.