make revlog.addgroup pass its file handles to addrevision
This should fix issue255.
It looks like the problem there happens when addgroup calls addrevision
to add a full revision, and addrevision decides to split the index file
into a .i/.d pair. Since addgroup has an open file handle for the
index file, the renaming of the new .i file to its final name fails on
windows.
<table class="slogEntry parity#parity#">
<tr>
<td class="age">#date|age#</td>
<td class="author">#author|obfuscate#</td>
<td class="node"><a href="#url#rev/#node|short#{sessionvars%urlparameter}">#desc|strip|firstline|escape#</a></td>
</tr>
</table>