Documentation: Remove mentions of git-svnimport.

git-svnimport is no longer supported, so don't mention it in the
documentation.  This also updates the description, removing the
historical discussion, since it mostly dealt with how it differed from
svnimport.  The new description gives some starting points into the
rest of the documentation.

Noticed by Jurko Gospodnetić <jurko.gospodnetic@docte.hr>

Signed-off-by: Brian Gernhardt <benji@silverinsanity.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-svn.txt

@@ -12,18 +12,18 @@ SYNOPSIS
 DESCRIPTION
 -----------
 'git-svn' is a simple conduit for changesets between Subversion and git.
-It is not to be confused with linkgit:git-svnimport[1], which is
-read-only.
+It provides a bidirectional flow of changes between a Subversion and a git
+respository.
 
-'git-svn' was originally designed for an individual developer who wants a
-bidirectional flow of changesets between a single branch in Subversion
-and an arbitrary number of branches in git.  Since its inception,
-'git-svn' has gained the ability to track multiple branches in a manner
-similar to 'git-svnimport'.
+'git-svn' can track a single Subversion branch simply by using a
+URL to the branch, follow branches laid out in the Subversion recommended
+method (trunk, branches, tags directories) with the --stdlayout option, or
+follow branches in any layout with the -T/-t/-b options (see options to
+'init' below, and also the 'clone' command).
 
-'git-svn' is especially useful when it comes to tracking repositories
-not organized in the way Subversion developers recommend (trunk,
-branches, tags directories).
+Once tracking a Subversion branch (with any of the above methods), the git
+repository can be updated from Subversion by the 'fetch' command and
+Subversion updated from git by the 'dcommit' command.
 
 COMMANDS
 --------
@@ -218,8 +218,7 @@ Any other arguments are passed directly to 'git-log'
 
 'commit-diff'::
 	Commits the diff of two tree-ish arguments from the
-	command-line.  This command is intended for interoperability with
-	'git-svnimport' and does not rely on being inside an `git-svn
+	command-line.  This command does not rely on being inside an `git-svn
 	init`-ed repository.  This command takes three arguments, (a) the
 	original tree to diff against, (b) the new tree result, (c) the
 	URL of the target Subversion repository.  The final argument
@@ -317,8 +316,7 @@ config key: svn.findcopiesharder
 -A<filename>::
 --authors-file=<filename>::
 
-Syntax is compatible with the files used by 'git-svnimport' and
-'git-cvsimport':
+Syntax is compatible with the file used by 'git-cvsimport':
 
 ------------------------------------------------------------------------
 	loginname = Joe User <user@example.com>