Only ever return pom path for type=pom

This closes #1730

Author: kwin

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

@@ -25,7 +25,6 @@
 import org.eclipse.aether.repository.WorkspaceRepository;
 import org.eclipse.aether.util.version.GenericVersionScheme;
 import org.eclipse.aether.version.InvalidVersionSpecificationException;
-import org.eclipse.aether.version.Version;
 import org.eclipse.aether.version.VersionConstraint;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IResource;
@@ -77,8 +76,8 @@ protected File resolveAsEclipseProject(String groupId, String artifactId, String
 
     if(context.resolverConfiguration.isResolveWorkspaceProjects()) {
       IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
-      IPath file = pom.getLocation();
-      if(file == null) {
+      IPath pomFile = pom.getLocation();
+      if(pomFile == null) {
         return ProjectRegistryManager.toJavaIoFile(pom);
       }
       if(!POM_EXTENSION.equals(extension)) {
@@ -94,12 +93,13 @@ protected File resolveAsEclipseProject(String groupId, String artifactId, String
         if(location != null) {
           IResource res = root.findMember(location);
           if(res != null) {
-            file = res.getLocation();
+            return res.getLocation().toFile();
           }
         }
+        return null;
+      } else {
+        return pomFile.toFile();
       }
-
-      return file.toFile();
     }
 
     return null;