Update to shade plugin 2.2 to shade test artifact as well

When we want to use test artifact in other projects, dependencies
are not shaded as for core artifact.

Issue opened in maven shade project: [MSHADE-158](http://jira.codehaus.org/browse/MSHADE-158)

When using it in other projects, you basically need to change your `pom.xml` file:

```xml
<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>${elasticsearch.version}</version>
    <type>test-jar</type>
    <scope>test</scope>
</dependency>
```

You can also define some properties:

```xml
<properties>
    <tests.jvms>1</tests.jvms>
    <tests.shuffle>true</tests.shuffle>
    <tests.output>onerror</tests.output>
    <tests.client.ratio></tests.client.ratio>
    <es.logger.level>INFO</es.logger.level>
</properties>
```