Defer seed_rng until after closefrom call.

seed_rng will initialize OpenSSL, and some engine providers (eg Intel's
QAT) will open descriptors for their own use.  bz#3483, patch from
joel.d.schuetze at intel.com, ok djm@

sshd.c

@@ -1580,8 +1580,6 @@ main(int ac, char **av)
 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 	sanitise_stdfd();
 
-	seed_rng();
-
 	/* Initialize configuration options to their default values. */
 	initialize_server_options(&options);
 
@@ -1703,6 +1701,8 @@ main(int ac, char **av)
 	else
 		closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
 
+	seed_rng();
+
 	/* If requested, redirect the logs to the specified logfile. */
 	if (logfile != NULL)
 		log_redirect_stderr_to(logfile);