Remove /etc/zfs/zdev.conf from configuration files and remove zdev.conf examples

Remove /etc/zfs/zdev.conf from configuration files and remove zdev.conf examples

  * /etc/zfs/zdev.conf should not be a configuration file.
	This is by policy:
	E.2 Fully-featured maintainer script configuration handling
	http://www.debian.org/doc/debian-policy/ap-pkg-conffiles.html

	This kind of site-specific configuration files should not be added
	to the package files.
	You don't want this file to be removed when you purge the package.

  * zdev.conf is not longer supported by upstream. We are carring a patch
    patches/0001-Revert-Retire-zpool_id-infrastructure.patch that I would
    like to remove ASAP.

    * Remove also all the examples related to zdev.conf shipped.
      Users should use vdev_id.conf instead.

 [!] Don't add vdev_id.conf to configuration files.