map-feature will throw if map-geometry doesn't contain a descendant map-(shape)

[prushforth]

To reproduce, paste the feature into a map:

<map-feature id="tasmania_cities.1" class="tasmania_cities">
  <map-geometry>
    <map-geometrycollection>
      <point>
        <map-coordinates>147.29100045 -42.85100182</map-coordinates>
      </point>
    </map-geometrycollection>
  </map-geometry>
</map-feature>

See: geosolutions-it/geoserver#363 (comment)