fix incorrect warning when walking on a particular rev when a directory was given instead of a file it reported incorrectly 'No such file or directory in rev <rev>' we test if the file is a prefix directory

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    <title>#tag|escape#</title>
    <link>#url#?cs=#node|short#</link>
    <description><![CDATA[#tag|strip|escape|addbreaks#]]></description>
    <pubDate>#date|rfc822date#</pubDate>
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