This patch changes the workflow for whole disk images when using uefi.
If we can identify the bootloader and it's valid we can update using
efibootmgr since grub2-install have problems specially on secure boot
mode.
We also updated the regex to search for the uefi partition on the disk,
since in some cases the parted command output can be without the FS
for the partition with esp Flag.
Change-Id: I7167e71e5d2352a045565289b200e5530d0ba11d
Story: #2006847
Task: #37435
b6210be196