jmod and modular MR jars

[Ryan Schmitt]

I noticed that `jmod create` seems to work fine when module-info.class is
located in the root of the jar supplied on the classpath, but when it is
located at META-INF/versions/9/module-info.class I get a stack trace
instead:

Error: module-info.class not found
java.io.IOException: module-info.class not found
at jdk.jlink/jdk.tools.jmod.JmodTask$JmodFileWriter.
writeModuleInfo(JmodTask.java:538)
at jdk.jlink/jdk.tools.jmod.JmodTask$JmodFileWriter.write(JmodTask.java:476)
at jdk.jlink/jdk.tools.jmod.JmodTask.create(JmodTask.java:433)
at jdk.jlink/jdk.tools.jmod.JmodTask.run(JmodTask.java:208)
at jdk.jlink/jdk.tools.jmod.Main.main(Main.java:34)

Is this a bug?