test-convert-svn-source: fix non-determinism

This test was failing randomly with:

  --- /tests/test-convert-svn-source.t
  +++ /tests/test-convert-svn-source.t.err
  @@ -35,8 +35,8 @@

     $ svnurl="file://$svnpath/svn-repo/proj%20B"
     $ svn import -m "init projB" projB "$svnurl" | fixpath
  +  Adding         projB/tags
     Adding         projB/mytrunk
  -  Adding         projB/tags

     Committed revision 1.

tests/test-convert-svn-source.t

@@ -34,10 +34,10 b' Initial svn import'
   $ cd ..
 
   $ svnurl="file://$svnpath/svn-repo/proj%20B"
-  $ svn import -m "init projB" projB "$svnurl" | fixpath
+  $ svn import -m "init projB" projB "$svnurl" | fixpath | sort
+  
   Adding         projB/mytrunk
   Adding         projB/tags
-  
   Committed revision 1.
 
 Update svn repository