CDRIVER-1044 declare the proper prototype

Oddly enough, it only affected Suse12 on zSeries

call to function 'mongoc_stream_tls_openssl_bio_set_data'
without a real prototype [-Werror=unprototyped-calls]

Author: bjori

src/mongoc/mongoc-stream-tls-openssl-bio-private.h

@@ -34,7 +34,7 @@ BIO_METHOD *
 mongoc_stream_tls_openssl_bio_meth_new ();
 
 void
-mongoc_stream_tls_openssl_bio_set_data ();
+mongoc_stream_tls_openssl_bio_set_data (BIO *b, void *ptr);
 
 int
 mongoc_stream_tls_openssl_bio_create (BIO *b);