fix integration.test_icontainer.testGetImagesBySplitFilesetsManyCases

Fixes `integration.test_icontainer` failure from http://trac.openmicroscopy.org.uk/ome/ticket/11610 so that there should be no skips or failures at http://hudson.openmicroscopy.org.uk/job/OmeroPy-integration-develop/lastSuccessfulBuild/testReport/test.integration.test_icontainer/.

--no-rebase as FS-specific