ipatopologysegment: Fail for missing entry with reinitialized

Currently it is ignored if the entry for reinitialized can not be found if
the name or left and right are not correct. Now there is a failure in this
case.

Fixes: #107 (Reinitialize are failed to find the node in ipatopology ..)
Signed-off-by: Thomas Woerner <twoerner@redhat.com>