Remove M2E lifecycle-mapping <ignore/> for maven-checkstyle-plugin
Remove M2E lifecycle-mapping <ignore/> for maven-checkstyle-plugin

This blocks Checkstyle for Controller from working in-IDE in
https://github.com/vorburger/opendaylight-eclipse-setup.  If a
individual developer still wants to disable it, that is still possible
locally, via menu Window > Preferences > Maven > Lifecycle Mapping.

Change-Id: I40d98cba30aa999fafebcbd82c6ea53696e971f0
Signed-off-by: Michael Vorburger <4d49e7cce9f97fb576795ab27509f7ee282641f6@redhat.com>

opendaylight/controller