Bug fix: passing self.ui to first parameter (topic)

self.ui was inadvertently passed again to the first argument, which really should be the topic variable.

When used from tortoisehg, an attempt to then decode this variable results in:

   #!python
    ** Mercurial version (2.9).  TortoiseHg version (2.11)
    ** Command: --nofork clone
    ** CWD: D:\Gary
    ** Encoding: cp1252
    ** Extensions loaded: hggit
    ** Python version: 2.7.6 (default, Nov 10 2013, 19:24:24) [MSC v.1500 64 bit (AMD64)]
    ** Windows version: sys.getwindowsversion(major=6, minor=1, build=7601, platform=2, service_pack='Service Pack 1')
    ** Processor architecture: x64
    ** Qt-4.8.5 PyQt-4.10.3 QScintilla-2.7.2
    Traceback (most recent call last):
      File "tortoisehg\hgqt\thread.pyo", line 287, in run
      File "tortoisehg\util\hglib.pyo", line 711, in dispatch
      File "mercurial\dispatch.pyo", line 806, in _dispatch
      File "mercurial\dispatch.pyo", line 586, in runcommand
      File "mercurial\dispatch.pyo", line 897, in _runcommand
      File "mercurial\dispatch.pyo", line 868, in checkargs
      File "mercurial\dispatch.pyo", line 803, in <lambda>
      File "mercurial\util.pyo", line 511, in check
      File "mercurial\commands.pyo", line 1310, in clone
      File "mercurial\hg.pyo", line 373, in clone
      File "mercurial\localrepo.pyo", line 2402, in clone
      File "C:\hg-git\hggit\hgrepo.py", line 14, in pull
      File "C:\hg-git\hggit\git_handler.py", line 201, in fetch
      File "C:\hg-git\hggit\git_handler.py", line 1007, in fetch_pack
      File "dulwich\client.pyo", line 542, in fetch_pack
      File "dulwich\client.pyo", line 406, in _handle_upload_pack_tail
      File "dulwich\client.pyo", line 287, in _read_side_band64k_data
      File "C:\hg-git\hggit\git_handler.py", line 69, in progress
      File "C:\hg-git\hggit\git_handler.py", line 86, in flush
      File "tortoisehg\hgqt\thread.pyo", line 131, in progress
      File "tortoisehg\hgqt\thread.pyo", line 84, in progress
      File "tortoisehg\util\hglib.pyo", line 48, in tounicode
    AttributeError: 'QtUi' object has no attribute 'decode'