Warnings/errors on duplicate lifecycle phases

[marcphilipp]

When invoking Maven with redundant lifecycle phases, e.g. mvn clean package verify install, goals are executed multiple times even though that's rarely what was intended. In the example, it was probably mvn clean install so one option would be to issue a warning and execute that instead. Another option would be to fail such invocations to educate developers that they're wasting time and resources and tell them what to do instead.

[slawekjaranowski]

https://issues.apache.org/jira/browse/MNG-5885

[khmarbaise]

We should fail that build and give hints what should be done in a better way.