TEIIDDES-2120: Erroneous relativising of path value

* Seems making the path relative to the tmp folder is not a good idea
  since it adds a ../ to its beginning. This causes the createTempFile
  method to fail.

* Causes preview vdbs creation to fail with a "no such file or directory"
  error

* Originally added to stop path being a full duplication of tmpFolder,
  which occurred in some unit tests. However, this does not seem to be
  repeated so removing.