odt2mediawiki.xsl: hide table of contents if there is a customized toc

Change-Id: I3be7f0929db94658ac1eabb0996364f53b52034c
Reviewed-on: https://gerrit.libreoffice.org/15795Tested-by: David Tardon <dtardon@redhat.com>
Reviewed-by: David Tardon <dtardon@redhat.com>

swext/mediawiki/src/filter/odt2mediawiki.xsl

@@ -296,6 +296,8 @@
 	</template>
 
 	<template match="text:index-title">
+		<text>__NOTOC__</text>
+		<value-of select="$NL"/>
 		<text>== </text>
 		<apply-templates/>
 		<text> ==</text>