Remove EVP_aead_chacha20_poly1305_rfc7539 alias.

This slipped through, but all the callers are now using
EVP_aead_chacha20_poly1305, so we can remove this version.

Change-Id: I76eb3a4481aae4d18487ca96ebe3776e60d6abe8
Reviewed-on: https://boringssl-review.googlesource.com/7650
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>

crypto/cipher/e_chacha20poly1305.c

@@ -244,10 +244,6 @@ const EVP_AEAD *EVP_aead_chacha20_poly1305(void) {
   return &aead_chacha20_poly1305;
 }
 
-const EVP_AEAD *EVP_aead_chacha20_poly1305_rfc7539(void) {
-  return EVP_aead_chacha20_poly1305();
-}
-
 static void poly1305_update_old(poly1305_state *ctx, const uint8_t *ad,
                                 size_t ad_len, const uint8_t *ciphertext,
                                 size_t ciphertext_len) {

include/openssl/aead.h

@@ -331,14 +331,6 @@ OPENSSL_EXPORT int EVP_AEAD_CTX_get_iv(const EVP_AEAD_CTX *ctx,
                                        const uint8_t **out_iv, size_t *out_len);
 
 
-/* Deprecated functions. */
-
-/* EVP_aead_chacha20_poly1305_rfc7539 calls |EVP_aead_chacha20_poly1305|.
- *
- * TODO(davidben): Remove this. */
-OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305_rfc7539(void);
-
-
 #if defined(__cplusplus)
 }  /* extern C */
 #endif