[SCSI] be2iscsi: adding functionality to change network settings using iscsiadm

This patch allows iscsiadm to set/ delete static IP and enable /disable
DHCP.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>