Fixes a regression introduced in [r4642]. N.450 Impact analysis. The previous fix aimed at generating more redundancy nodes, but in fact it generated too many in some circumstances.
Fixes a regression introduced in [r4642]. N.450 Impact analysis. The previous fix aimed at generating more redundancy nodes, but in fact it generated too many in some circumstances.

git-svn-id: 8a2b0a969c74f87a9c14cf35f460fb9b394f82c6@4649 a333f486-631f-4898-b8df-5754b55c2be0

changi67/itop,changi67/itop,changi67/itop,changi67/itop