bookmarks: primarily use repo lock, not wlock
Bookmarks are repository data, not working directory data. Only the current
bookmark is working directory data.
Some lock shuffling is required to avoid lockout between the initial mock lock
and locking of the localrepo instance that is created after copying.
<item>
<title>{desc|strip|firstline|strip|escape}</title>
<guid isPermaLink="true">{urlbase}{url}rev/{node|short}</guid>
<description><![CDATA[{desc|strip|escape|addbreaks|nonempty}]]></description>
<author>{author|obfuscate}</author>
<pubDate>{date|rfc822date}</pubDate>
</item>