Make header signature of CRYPTO_mem_leaks BIO instead of struct bio_st

Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1012)

include/openssl/crypto.h

@@ -409,7 +409,7 @@ void CRYPTO_mem_debug_free(void *addr, int flag,
 #  ifndef OPENSSL_NO_STDIO
 int CRYPTO_mem_leaks_fp(FILE *);
 #  endif
-int CRYPTO_mem_leaks(struct bio_st *bio);
+int CRYPTO_mem_leaks(BIO *bio);
 # endif
 
 /* die if we have to */