ubuntu-signed element would install 'linux-signed-image-generic' that
provides signed kernel that can be used for deploy in UEFI secure boot mode.
Package 'linux-signed-image-generic' ships signed kernel with extension
'.efi.signed' (Ex. '/boot/vmlinuz-3.13.0-49-generic.efi.signed').
The kernel modules directory for signed kernel and unsigned kernel is same.
It is without 'efi.signed' extension to its name. This is different from normal
practice of directory naming in '/lib/modules' (Ex. For signed kernel
'vmlinuz-3.13.0-49-generic.efi.signed', modules directory is
'/lib/modules/3.13.0-49-generic').
This needed some changes in '/lib/ramdisk-functions' and 'ramdisk' element to
copy kernel modules.
The signed kernel package contains both signed and unsigned kernel. The
unsiged kernel is without extension '.efi.signed' (Ex.
'/boot/vmlinuz-3.13.0-49-generic'). This required change into
'/lib/img-functions' and 'baremetal' element to pick up signed kernel version
when this element is used.
Closes-Bug: 1443076
Change-Id: I60061cbea847b47fa752b9463cfd387e8e7f0635
