wix: bump MSI based installers to use Python 2.7

We're somewhat forced to use Python 2.7 for the bdist packages, so we might
as well use 2.7 for the MSI installers as well.

contrib/wix/dist.wxs

@@ -1,31 +1,31 b''
 <?xml version="1.0" encoding="utf-8"?>
 <Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
 
   <?include guids.wxi ?>
   <?include defines.wxi ?>
 
   <Fragment>
     <DirectoryRef Id="INSTALLDIR" FileSource="$(var.SourceDir)">
       <Component Id="distOutput" Guid="$(var.dist.guid)" Win64='$(var.IsX64)'>
         <File Name="library.zip" KeyPath="yes" />
         <File Name="mercurial.base85.pyd" />
         <File Name="mercurial.bdiff.pyd" />
         <File Name="mercurial.diffhelpers.pyd" />
         <File Name="mercurial.mpatch.pyd" />
         <File Name="mercurial.osutil.pyd" />
         <File Name="mercurial.parsers.pyd" />
         <File Name="pyexpat.pyd" />
-        <File Name="python26.dll" />
+        <File Name="python27.dll" />
         <File Name="bz2.pyd" />
         <File Name="select.pyd" />
         <File Name="unicodedata.pyd" />
         <File Name="_ctypes.pyd" />
         <File Name="_elementtree.pyd" />
         <File Name="_hashlib.pyd" />
         <File Name="_socket.pyd" />
         <File Name="_ssl.pyd" />
       </Component>
     </DirectoryRef>
   </Fragment>
 
 </Wix>