This is so we don't break 'lbu package -'

This patch fixes bug #419:
http://redmine.alpinelinux.org/issues/419

Problem exists in Alpine Linux 2.0.0.

This patch updates setup-disk to correctly add swap to the fstab and
add the swap service to the boot runlevel.

And print summary of the interface configuration

new busybox doesnt support the old way we did it.

so we can generate the certificate

+ misc fixes

lbu did bad things with your /dev/null

It is old and not used anymore

mdadm 3.1.1 switched to use metadata 1.1 by default. This does not work
with extlinux so we set metadata to old default manually for /boot.

also, fix issue when /var/lib/apk/installed is included

this works around an issue when lbu wrongly assumes /media/usb is
mounted when /media/usbdisk is.

ref #91

scripts in /etc/lbu/pre-package.d/ will be executed prior creating the
tar ball and scripts in /etc/lbu/post-package.d/ will be executed after.

if pre-scripts fails, then will package not be created.

ref #220