trivial fixes to node.xml
node.xml: remove useless zfs_img.conf file

This file is not used any where... So we should not create it
node.xml: rocks sync user must be run after useradd
node.xml: fix error udev setup
node.xml: first take at partitioning with zfs and mirror

create a sample default partitioning script which does:
first 20GB to /
the remaining used by zfs in a pool called &vm_container_zpool;

If there are two disks, they are mirrored (both the / FS and the
zpool are mirrored).
usersguide: minor fixes mostly formatting
usersguide: added a table with all attributes

added a table with a list of all attribute used by the img-storage
roll to help the user understand them
node.xml: fix partitioning for node with 1 disk
node.xml: properly set permission to /dev/zfs

udev cache rules with GID at boot times so if the group is not
defined when the machine boot it will never be applyed properly

For this reason we need to touch the file containing the rule
so udevd will reload the group->GID association for that rule
After that the udevadm trigger will do its job and set the
permissions properly

1 day to debug this :-(