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: I22dac8524ce8acb033dc9c72eab107999f49f975
diff --git a/debian/rules b/debian/rules
index 0d602e5..616f96d 100755
--- a/debian/rules
+++ b/debian/rules
@@ -24,7 +24,3 @@
 # Print test results in case of a failure
 override_dh_auto_test:
 	dh_auto_test || (find . -name testsuite.log -exec cat {} \; ; false)
-
-override_dh_autoreconf:
-	echo $(VERSION) > .tarball-version
-	dh_autoreconf