Fix indentation of previous changelog entry.

It breaks parsechangelog.

debian/changelog

@@ -175,7 +175,7 @@ tails (1.3) unstable; urgency=medium
       Vagrant. We need version 6.03~pre20 to make the Tails ISO image
       in hybrid mode
     - Update deb.tails.boum.org apt repo signing key. (Closes: #8747)
-	- Revert "Workaround build failure in lb_source, after creating
+    - Revert "Workaround build failure in lb_source, after creating
       the ISO." This is not needed anymore given the move to the Tor
       SOCKS proxy. (Closes: #5307)
     - Remove the bootstrap stage usage option and disable all