This commit fixes both failure of test itself and failure of compiling
and running test.
- When the test was run via 'mvn test', Maven gives karaf-maven-plugin a
list of class directories instead of OSGi bundles, so that
karaf-maven-plugin generates incorrect feature.xml. I added a
workaround for this specific case to DependencyIT
- When the packaging of project is 'feature', maven-compiler-plugin is
not run at all. Added a <plugin/> section so that it's always
compiled.