Description of problem:
I install rhev-hypervisor6-6.5-20140930.1.el6ev iso to an iSCSI target. Then change the kernel arguement to boot from the iSCSI target, after a while the kernel crashed and report the error as beloew:
dracut Warning: No root device "/dev/live-rw" found
kernel panic - not syncing : attempted to kill init!

while there is no such problem in rhev-hypervisor7-7.1-20150603.0.el6ev!

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1. setup ipxe network boot enviroment in RHEL 7.1, using sanboot to boot from iSCSI target
2. setup iSCSI target in the same eviroment in RHEL 7.1
3. install rhev-hypervisor6-6.5-20140930.1.el6ev into iSCSI target by creating a vm in RHEV-M which has a direct lun to the iSCSI target
4. change the kernel arguement like below: 
 kernel /vmlinuz0 root=live:LABEL=Root rw rootfstype=auto rootflags=rw ifname=eth0:00:1a:4a:78:df:56 netroot=iscsi:@172.30.4.219::3260:iface0:eth0::iqn.vanlos.com:rhev-h ip=eth0:dhcp iscsi_initiator=iqn.vanlos.com:rhev-h crashkernel=auto max_loop=256 rd_NO_LUKS rd_NO_MD rd_NO_DM

Actual results:
kernel crashed while system booting

Expected results:
successfully boot into the system

Additional info:
The same produce for setup rhev-hypervisor7-7.1 can boot into system from iSCSI target.