quagga: fix pkg_postinst

This patch mainly involves two changes.
1. Create necessary files at do_install task. Add these configuration
   files to the CONFFILES variable.
2. Move the `chmod' and `chown' commands to do_install task.

After these two changes, qugga can run successfully at rootfs time.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Joe MacDonald <joe@deserted.net>