Description of problem:  
Using "livecd-iso-to-disk --format --efi .." to make EFI booting usb media failed in rhel7 env. 
[root@dhcp-8-228 edit-node]# livecd-iso-to-disk --format --efi rhev-hypervisor7-7.0-20140806.1.iso /dev/sdb
Verifying image...
/home/edit-node/rhev-hypervisor7-7.0-20140806.1.iso:   4809bf075cd6cfe870f8214508b3d630
Fragment sums: 53c9e65132e3198b95589f2d24aa19e391f5458dd82abb59134f6d964e1e
Fragment count: 20
Press [Esc] to abort check.
Checking: 100.0%

The media check is complete, the result is: PASS.

It is OK to use this media.
WARNING: THIS WILL DESTROY ANY DATA ON /dev/sdb!!!
Press Enter to continue or ctrl-c to abort

/dev/sdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 8 bytes were erased at offset 0x3c902fe00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/sdb: calling ioclt to re-read partition table: Success
Waiting for devices to settle...
mkfs.fat 3.0.20 (12 Jun 2013)
ERROR: This live image does not support EFI booting


Version-Release number of selected component (if applicable):
ovirt-node-3.1.0-0.7.20140806gitef5c5cb.el7.noarch
rhev-hypervisor7-7.0-20140806.1.iso        

How reproducible:
100%


Steps to Reproduce:


Actual results:

Expected results:

Additional info:
no this issue in rhev-hypervisor6-6.5-20140725.0.iso with the same env, so
it's a regression bug