Let infinispan-parent inherit from infinispan-bom

infinispan-parent currently has a dependency on infinispan-bom with scope import. Properties declared in infinsipan-bom are thus not visible to child modules (those inheriting from infinispan-parent).

The suggestion is to let infinispan-parent inherit from infinispan-bom, which is in-line with http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html and makes it possible to access properties declared in infinispan-bom (such as version.protostream)