Fix #8: kernel messages duplicated to console

When building the sysklogd project --without-klogd we must disable the
kernel logging to console on Linux.  This fix depends on how the sysctl
setting `kernel.printk` is configured.  The patch only calls the kernel
to set console_loglevel to minimum_console_loglevel.

See the kernel docs for details:

  https://www.kernel.org/doc/Documentation/sysctl/kernel.txt

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/syslogd.c

@@ -385,6 +385,8 @@ int main(int argc, char *argv[])
 	/* Attempt to open kernel log pipe */
 	if (opensys(_PATH_KLOG))
 		warn("Kernel logging disabled, failed opening %s", _PATH_KLOG);
+	else
+		kern_console_off();
 #endif
 
 	if (!Foreground) {
@@ -2016,6 +2018,10 @@ void die(int signo)
 		free(pe);
 	}
 
+#ifndef KLOGD
+	kern_console_on();
+#endif
+
 	exit(0);
 }