evaluate DonePackage callback

- to close the package installation progress popup when package installation
  is finished ([bnc#842465](https://bugzilla.novell.com/show_bug.cgi?id=842465))
- (fix up for the previous commit, see https://github.com/yast/yast-pkg-bindings/commit/f91b509cc94c4078904c7716d059ad9d7083bc1e#diff-b7716b0bc5985f9d1615a5495f7550d8L325, the call was by mistake removed)
- 3.0.3