Anaconda can't find repos when boot from usb stick

[Maksym Strukov]

Steps:
1. Write Fuel to usb stick or attach iso image to qemu as usb drive
2. Boot Fuel from usb
3. On grub menu press Esc and use custom cmd as following:
vmlinuz initrd=initrd.img biosdevname=0 repo=hd:LABEL=Mirantis_Fuel:/ ks=hd:LABEL=Mirantis_Fuel:/ks.cfg ip=10.109.25.2::10.109.25.1:255.255.255.0:nailgun.test.domain.local:enp0s3:off::: dns1=8.8.8.8 showmenu=0 wait_for_external_config=yes build_images=0
4. Press Enter (to boot) and wait

Expected:
Any user input don't needed. Fuel installation complete successfully

Actual:
See attached screenshot. For some reasons anaconda can't find repos.

Env: 9.0-8
Available on srv72-bud.infra.mirantis.net with command
'''
source /home/jenkins/venv-nailgun-tests-2.9/bin/activate; dos.py revert-resume 9.0.system_test.ubuntu.thread_usb.32.32 error_setup_master && ssh root@10.109.15.2
'''

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/288007