In case there is a file on the volume storage that is exactly two bytes
long, BasicFilenameDecryptionStrategy.decryptImpl() will end up with a
zero length encFileName which will trigger unhandled exceptions from
EncFSCrypto calls. Handle the exception in decryptImpl() instead.
It's possible for a malformed file name to result in a decoded file
name that is smaller than 2 bytes. The fix is to catch the exception and
throw an EncFSCorruptDataException.
