Expose UNF in dvExtractFileIds

[leeper]

Here's an example. UNF is in a notes attribute with attribute subject='Universal Numeric Fingerprint':

<fileDscr ID="f2228893" URI="http://thedata.harvard.edu/dvn/dv/leeper/FileDownload/Study+2+%28Exit+Poll%29+Data.tab?fileId=2228893">
<fileTxt>
<fileName>Study 2 (Exit Poll) Data.tab</fileName>
<fileCont>Study 2 Data</fileCont>
<dimensns>
<caseQnty>765</caseQnty>
<varQnty>22</varQnty>
</dimensns>
<fileType>text/tab-separated-values</fileType>
</fileTxt>
<notes level="file" type="VDC:UNF" subject="Universal Numeric Fingerprint">UNF:5:lq240i2xO+fIXWfvAeIJCg==</notes>
<notes type="vdc:category">Data</notes>
</fileDscr>