fix: close stdin and stdout only in repmgrd

closing stdin and stdout might cause problems when using system(), so we
avoid it.

log.c

@@ -140,9 +140,6 @@ bool logger_init(t_configuration_options *opts, const char* ident, const char* l
 
 #endif
 
-	fclose(stdin);
-	fclose(stdout);
-
 	if (*opts->logfile)
 	{
 		freopen(opts->logfile, "a", stderr);