Less exception in standard file.

* src/dctc/java/com/dataiku/dctc/file/StandardFile.java: Allow more
  operation (dctc cp foo -).
wtf: What was this code for?

* src/dctc/java/com/dataiku/dctc/copy/SimpleCopyTaskRunnableFactory.java:
  Don't understand what this code here. Delete it.