Add check for empty String for the local directory in addition to null.
Add logging to detect why return null.
wrong param name in comment
turned off krb so mac users using java 7 can run tests
Merge pull request #476 from dcapwell/testdfsio-mac

turned off krb so mac users using java 7 can run tests
Merge pull request #475 from CrazyJvm/StorageDir-comment

StorageDir : wrong param name in comment
Merge pull request #439 from hsaputra/add_logging_localtempfolder

Add check for empty String for the local directory in addition to null and add logging.
tweak TachyonFS logging.