keyword: avoid traceback when kwdemo is run outside a repo

f0564402d059 causes a fatal AttributeError if kwdemo is run outside a repo
because in the temporary repo creation repo is None and therefore cannot have a
baseui attribute.
In this case fall back to using ui.

Add test case.

hgext/keyword.py

@@ -412,7 +412,11 b' def demo(ui, repo, *args, **opts):'
     fn = 'demo.txt'
     tmpdir = tempfile.mkdtemp('', 'kwdemo.')
     ui.note(_('creating temporary repository at %s\n') % tmpdir)
-    repo = localrepo.localrepository(repo.baseui, tmpdir, True)
+    if repo is None:
+        baseui = ui
+    else:
+        baseui = repo.baseui
+    repo = localrepo.localrepository(baseui, tmpdir, True)
     ui.setconfig('keyword', fn, '', 'keyword')
     svn = ui.configbool('keywordset', 'svn')
     # explicitly set keywordset for demo output

tests/test-keyword.t

@@ -1,3 +1,15 b''
+Run kwdemo outside a repo
+  $ hg -q --config extensions.keyword= --config keywordmaps.Foo="{author|user}" kwdemo
+  [extensions]
+  keyword =
+  [keyword]
+  demo.txt = 
+  [keywordset]
+  svn = False
+  [keywordmaps]
+  Foo = {author|user}
+  $Foo: test $
+
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > keyword =