The single pass algorithm removed a1, added b2, then removed a2 and a3,
which caused the wrong memory map to be built. The two pass algorithm
removes a1, a2, and a3, then adds b1.
Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>