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.

Change-Id: I08fa724a9a70e024845f683fb3f5d245a0bd9aa3
Related: OS#3449

debian/rules

@@ -8,10 +8,6 @@ VERSION := $(shell echo '$(DEBVERS)' | sed -e 's/[+-].*//' -e 's/~//g')
 %:
 	dh $@ --with autoreconf
 
-override_dh_autoreconf:
-	echo $(VERSION) > .tarball-version
-	dh_autoreconf
-
 # See https://www.debian.org/doc/manuals/developers-reference/best-pkging-practices.html#bpp-dbg
 override_dh_strip:
 	dh_strip --dbg-package=libosmo-ranap-dbg