Current iso element uses 'search --file' to find the
grub root. This is a wrong approach as it may find
some other partition containing /vmlinuz. Instead modify
it to search for grub root by the label of ISO image.
Closes-Bug: 1384826
Change-Id: Id4217be3420597bed2f80a96788928259ec91582
This commit adds a new element named 'iso' to build a bootable
ISO image for the kernel/ramdisk emitted by the 'baremetal' or
'ramdisk' element.
Change-Id: I89d175a29e2d0bc64b47fe527f0d0f6875f6849a