git --diff: fix traceback when getting mode change
- use the manifest instead of the mode in the working dir
if the diff is against two revisions
- add a testcase
#header#
<title>#repo|escape#: searching for #query|escape#</title>
</head>
<body>
<div class="buttons">
<a href="?cl=tip">changelog</a>
<a href="?sl=tip">shortlog</a>
<a href="?tags=">tags</a>
<a href="?mf=#manifest|short#;path=/">manifest</a>
</div>
<h2>searching for #query|escape#</h2>
<form>
<p>
search:
<input type="hidden" name="cmd" value="changelog">
<input name="rev" type="text" width="30" value="#query|escape#">
</p>
</form>
#entries#
<form>
<p>
search:
<input type="hidden" name="cmd" value="changelog">
<input name="rev" type="text" width="30" value="#query|escape#">
</p>
</form>
#footer#