Bug#789802: lintian: False positive source-contains-prebuilt-java-object reported against jar files without classes

[Emmanuel Bourg]

apache-log4j2 is another example, it contains an IntellijSettings.jar
file with IDE settings (plain text files, no compiled classes).

https://sources.debian.net/src/apache-log4j2/2.2-1/src/ide/Intellij/13/