bzr-doc still mentions bzr-svn

bzr-doc still mentions bzr-svn in its user guide, however bzr-svn has been removed from both saucy and debian/unstable because it's unmaintained. See https://bugs.launchpad.net/ubuntu/+source/bzr-svn/+bug/1182851

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: bzr-doc 2.6.0-3ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Mon Nov 25 14:42:24 2013
Dependencies:
 libjs-jquery 1.7.2+dfsg-2ubuntu1
 libjs-sphinxdoc 1.1.3+dfsg-7ubuntu2
 libjs-underscore 1.4.4-2ubuntu1
InstallationDate: Installed on 2013-05-24 (184 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: bzr
UpgradeStatus: Upgraded to saucy on 2013-10-19 (37 days ago)