Remove redundant include

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9137)

(cherry picked from commit f35819d1b7e195af9a41d991db00655f6f2c0af3)

include/openssl/bio.h

@@ -20,10 +20,6 @@
 # include <openssl/crypto.h>
 # include <openssl/bioerr.h>
 
-# ifndef OPENSSL_NO_SCTP
-#  include <openssl/e_os2.h>
-# endif
-
 #ifdef  __cplusplus
 extern "C" {
 #endif