filter: mark writer_MS_Word_97_Vorlage as preferred

The other filter associated with the .dot extension is
writer_MS_Word_95_Vorlage, obviously the 97 one should be preferred.
With having one filter as preferred for this extension, plain
'--convert-to dot' starts to work.

Change-Id: I7207d0fcb3c55b8dcc7b6179ccfa33a7c85d2ce8

filter/source/config/fragments/types/writer_MS_Word_97_Vorlage.xcu

@@ -20,7 +20,7 @@
         <prop oor:name="URLPattern"/>
         <prop oor:name="Extensions"><value>dot</value></prop>
         <prop oor:name="MediaType"><value>application/msword</value></prop>
-        <prop oor:name="Preferred"><value>false</value></prop>
+        <prop oor:name="Preferred"><value>true</value></prop>
         <prop oor:name="PreferredFilter"><value>MS Word 97 Vorlage</value></prop>
         <prop oor:name="UIName">
             <value>MS Word 97/2000 Template</value>