Fix HFileTargetIT failures on hadoop1 under Java 1.7/1.8

From the user mailing list, we're seeing that the dfs.data.dir permissions aren't getting set properly by the minicluster we use for HBase tests on HFileTargetIT. I put together a fix that involves tweaking the permissions ala HBASE-5711 by hand after trying a bunch of other things that didn't fix the underlying issues.