Karaf 4.2.5 maven plugin breaks if no archives are generated

Karaf 4.2.5 includes a line checking if archiveTarGz or archiveZip is selected, throwing an error otherwise. Unfortunately, this line breaks our build and a few of our use cases where we do not pack our assemblies.

For example, we have a development assembly which we have end up in a special folder unpacked and prepared to be launched. We could, of course, pack and then automatically unpack it but that would just be a waste of time.

We also have some assemblies which we pack with additional files (documentation, …) which is handled separately. Again a use-case for assemblies unpacked by the karaf-maven-plugin.

The change in question is:

https://github.com/apache/karaf/pull/811