Never return path to pom.xml for artifact files except for type = "pom"

[kwin]

Currently the logic in

m2e-core/org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/project/registry/EclipseWorkspaceArtifactRepository.java

Lines 84 to 102 in 5f94521

	if(!POM_EXTENSION.equals(extension)) {
	MavenProjectFacade facade = context.state.getProjectFacade(pom);
	IWorkspaceClassifierResolver resolver = MavenPlugin.getWorkspaceClassifierResolverManager().getResolver();
	IPath location = resolver.resolveClassifier(facade, classifier);
	if(location == null) {
	location = facade.getOutputLocation();
	}
	if(location != null) {
	IResource res = root.findMember(location);
	if(res != null) {
	file = res.getLocation();
	}
	}
	}
	return file.toFile();

may return the pom.xml path. This is used in

m2e-core/org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/project/registry/EclipseWorkspaceArtifactRepository.java

Line 145 in 5f94521

public org.apache.maven.artifact.Artifact find(org.apache.maven.artifact.Artifact artifact) {

(an implementation of the Maven SPI org.apache.maven.artifact.repository.ArtifactRepository) to set the artifact's file.

Although returning the path to the pom.xml makes sense for type being pom it doesn't for any other type. In that case one should rather fall back to null.