JBIDE-14710: Removes apache poi from locus

* Consumers should use the version contained in Orbit instead.
Small fixes to poms

* mockito/pom.xml
 * Remove kepler repository as TP provided in main pom

* pom.xml
 * Use 1.1.0 version of maven-download-plugin since 0.2 is no longer
   available
 * Provides a property for setting the version of the Eclipse TP

* site/pom.xml
 * Associate with the same version that was built against