[fedora-java] Subpackage assignment with mvn_artifact

[Christopher]

Hi,

I'm trying to get the thrift package to build again after %add_maven_depmap
has been moved to javapackages-local in rawhide (f27).
I'm trying to take the opportunity to switch to %mvn_artifact, but I can't
figure out how to do the subpackage assignment which used to be done with
the -f flag with %add_maven_depmap.

I've already read https://fedora-java.github.io/howto/latest/#mvn_artifact but
that doesn't seem to document subpackage assignment. The only mention says
to use %mvn_package, but this is an ant build, so that won't work.

Any assistance would be appreciated. Thanks.

Also, will %mvn_artifact work in EPEL7 and F25? I'd like to keep the spec
sync'd up across supported branches as much as possible.