Use the KDE SC version also as the Dolphin versions

Use the KDE SC version also as the Dolphin versions

This has some advantages:

(a) The version actually changes for every bug fix release, making it
    easier to find out which version a bug reporter has used.

(b) No changes in Dolphin's source code are required to keep the version
    always up to date.

(c) It is more transparent for users because there are not two different
    versions any more.