Set a Maven Property indicating if a database reused or created.

This feature can be useful to control the behaviour of subsequent Maven steps. For example, if a database is filled with default data, a user might want to skip this step if an existing database was reused. See “example-database-reuse.apt.vm” for an example.
OK, I agree, let's leave it. But, let's change the message. "MavenProject is null" is not informative to the end-user. Let's say something like "Maven plugin wasn't initialized correctly, we can't expose required properties". something like this