lispy.el: update semanticdb interaction

* lispy.el (lispy-build-semanticdb): Don't modify file in tags.
  (lispy--tag-name): Look at case when a vector is in place of overlay.
  (lispy--fetch-tags): Don't save db.
  (lispy--set-file-to-tags): Put file name in third place of position
  vector.
  (lispy--action-jump): Expects a vector of length 3 in place of
  overlay (beginning, end and file)