debian/rules: Don't overwrite .tarball-version

The .tarball-version file should contain the *source version* uniquely
identifying the git commit, and not the Debian package name.

With https://gerrit.osmocom.org/#/c/osmo-ci/+/10343/ there is a correct
.tarball-version file in the .tar.xz of the nightly source packages.

Related: OS#3449
Change-Id: I61a7995edf9fbc06db88ab391d32a988c3760c19
1 file changed