image-vmdk: Create image_vmdk class and setup image and image_types to use it
This creates a new image_vmdk class similar to live. The image_vmdk
class needs to have a hddimg created by the image-live class, so it
inherits it directly.
The changes to image_types is to ensure that both live and vmdk images
get the ext3 tools and dependencies.
Signed-off-by: Saul Wold <sgw@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
