gitweb: shortlog template: removed excessive whitespace, added title bar.
The title bar is currently empty, this is just a preparation for filling it
with content.
#header#
<title>Mercurial Error</title>
</head>
<body>
<h2>Mercurial Error</h2>
<p>
An error occured while processing your request:
</p>
<p>
#error|escape#
</p>
#footer#