Fix NPE when passing a null filter, which is marked as allowed.
<?xml version="1.0" encoding="UTF-8"?>
<project name="com.nokia.carbide.cpp.debug.crashdebugger" default="build.index" basedir=".">
<target name="build.index" if="eclipse.running" >
<help.buildHelpIndex manifest="${basedir}/plugin.xml" destination="${basedir}" />
</target>
</project>