-DprocessParent=true is ignored by user-reactor mojo

[amuniz]

processParent parameter is ignored by user-reactor mojo.

The failing use case is:

1. Hierarchical project structure: A <- B <- C (where A and B are <packaging>pom</packaging> and C is <packaging>jar</packaging>
2. Parent relationship is on releases (C parent is the latest release of B, and B parent is the latest release of A)
3. Run mvn versions:use-reactor -DprocessParent=true -DexcludeReactor=false -DallowSnapshots=true on A (the grandparent).
4. Expected: C parent is updated to point to current version of B in the reactor, same of B.
5. What I get: parents are not updated at all.