Added support for ZFS Storage Plugin

Added support for ZFS Storage Plugin

example of storage.cfg

zfs:    omnios
        blocksize 8k
        target iqn.2010-09.org.openindiana:target1
        pool pool1
        iscsiprovider comstar
        portal 192.168.0.1
        sudo 1  (optionnal)
        content images

note for fast ssh login:
on solaris  host :

/etc/ssh/sshd_config

LookupClientHostnames no
VerifyReverseMapping no
GSSAPIAuthentication no

note for nexenta:

rm /root/.bash_profile

to avoid to go in nmc console by default

Signed-off-by: Michael Rasmussen <mir@datanom.net>
Signed-off-by: Alexandre Derumier <aderumier@odiso.com>