ram: Remove SaveVM Version 2 support

It don't work.  It fails in this check

        if (qemu_get_be32(f) != last_ram_offset)

With 512MB of ram, values were for me:

	v = 20c00000 last_ram_offset = 20840000

Last time that some code changed that was this one.

    commit 94a6b54fd6d2d3321066cb4db7abeeb417af9365
    Implement dynamic guest ram allocation.
    (I.e. it has been broken since at least April)

Going back to the previous commit, ram load correctly, but vga screen gets
corrupted and ide don't load correctly.  At this point I decide that removing
support is the only viable thing.

The last user of the ram_compress_* were RAM_SAVE_FLAG_FULL flag, but
that flag was never ever been stored in an image. Mark the flag obsolete
and remove the functions.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
