downloadSources will not attach artifact-5-sources.jar to artifact-5-jar.jar

When depending on a project that has WAR as the default artifact, my project uses

<dependency>
<groupId>group</groupId>
<artifactId>artifact</artifactId>
<version>5</version>
<classifier>jar</classifier>
</dependency>

This results in no attached sources for that jar in Eclipse. m2eclipse has raised the same issue but in reverse: MNGECLIPSE-1649

It seems when building the project above, artifact-5-jar-sources.jar is produced in the target folder, but when installed to the local repo (and deployed to the remote repo), it renames the file to artifact-5-sources.jar

The diff attached changes the lookup behaviour to not include the classifier unless it's "tests". This will bring it in line with m2e's lookup.