Use correct name of sample java app jar.
Use correct name of sample java app jar.

Signed-off-by: Tyler Phelan <5713437ebd3bcae14564c2baaa7816b900ed174c@pivotal.io>

cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci