Allow the creating of fragments that populate Export-Package

When using the maven-bundle-plugin to create fragments which add export-packages to a host bundle, the maven-bundle-plugin considers all of the export-packages as superfluous, does not add them to the fragment's MANIFEST.MF file and fails to compile.

The specific case is when attempting to add exports to a bundle where bnd-wrapping doesn't pick up all of the necessary packages. For example, when executing this line in Karaf:
osgi:install -s mvn:tibco/tibco-crypt/5.1.2

The wrap command skips over a number of packages. So creation of a fragment is necessary. However, the build fails for the above noted reason. The work-around for this issue is to use the maven-jar-plugin to create the fragment.