Updated maven-idea-codestyle.xml for IntelliJ IDEA 14+

[Tibor Digana]

Hi,

In *apache/maven-site* [1], I have updated checkstyle for IntelliJ IDEA
because the new IDEA 14+ is not able to understand the old format.

[1]: https://github.com/apache/maven-site/pull/78

Cheers
Tibor