Move in_handshake into STATEM

The SSL variable |in_handshake| seems misplaced. It would be better to have
it in the STATEM structure.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>

ssl/s3_lib.c

@@ -5085,11 +5085,11 @@ static int ssl3_read_internal(SSL *s, void *buf, int len, int peek)
          * makes sense here; so disable handshake processing and try to read
          * application data again.
          */
-        s->in_handshake++;
+        ossl_statem_set_in_handshake(s, 1);
         ret =
             s->method->ssl_read_bytes(s, SSL3_RT_APPLICATION_DATA, NULL, buf,
                                       len, peek);
-        s->in_handshake--;
+        ossl_statem_set_in_handshake(s, 0);
     } else
         s->s3->in_read_app_data = 0;