Ensure s_client and s_server work when read_ahead is set

Previously s_client and s_server relied on using SSL_pending() which does
not take into account read_ahead. For read pipelining to work, read_ahead
gets set automatically. Therefore s_client and s_server have been
converted to use SSL_has_pending() instead.
Reviewed-by: NTim Hudson <tjh@openssl.org>

apps/s_client.c

@@ -2183,7 +2183,7 @@ int s_client_main(int argc, char **argv)
             }
         }
 
-        ssl_pending = read_ssl && SSL_pending(con);
+        ssl_pending = read_ssl && SSL_has_pending(con);
 
         if (!ssl_pending) {
 #if !defined(OPENSSL_SYS_WINDOWS) && !defined(OPENSSL_SYS_MSDOS) && !defined(OPENSSL_SYS_NETWARE)

apps/s_server.c

@@ -2213,7 +2213,7 @@ static int sv_body(int s, int stype, unsigned char *context)
         int read_from_sslcon;
 
         read_from_terminal = 0;
-        read_from_sslcon = SSL_pending(con)
+        read_from_sslcon = SSL_has_pending(con)
                            || (async && SSL_waiting_for_async(con));
 
         if (!read_from_sslcon) {
@@ -2451,7 +2451,7 @@ static int sv_body(int s, int stype, unsigned char *context)
                     ascii2ebcdic(buf, buf, i);
 #endif
                     raw_write_stdout(buf, (unsigned int)i);
-                    if (SSL_pending(con))
+                    if (SSL_has_pending(con))
                         goto again;
                     break;
                 case SSL_ERROR_WANT_ASYNC: