check for connect failure in syslog log opening

based on patch by Dima Krasner, with minor improvements for code size.
connect can fail if there is no listening syslogd, in which case a
useless socket was kept open, preventing subsequent syslog call from
attempting to connect again.

(cherry picked from commit c574321d75f035ff6d2c18dfb7e3f70db60ba7bd)

src/misc/syslog.c

@@ -45,8 +45,12 @@ void closelog(void)
 
 static void __openlog()
 {
-	log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
-	if (log_fd >= 0) connect(log_fd, (void *)&log_addr, sizeof log_addr);
+	int fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	if (fd < 0) return;
+	if (connect(fd, (void *)&log_addr, sizeof log_addr) < 0)
+		close(fd);
+	else
+		log_fd = fd;
 }
 
 void openlog(const char *ident, int opt, int facility)