Update RawFileStoreTest.java: Remove "broken" annotation from test.

http://hudson.openmicroscopy.org.uk/job/OmeroJava-broken-develop/lastCompletedBuild/testngreports/integration/integration.RawFileStoreTest/testDownloadScript/ is constantly green. This PR removes the "broken" group from the "@Test" annotation.

To test - verify that OmeroJava-integration-develop gained one passing test.