Fix histogram and rhqBar chart types.
Fix histogram and rhqBar chart types.

ammendonca/hawkular-charts,tsegismont/hawkular-charts,tsegismont/hawkular-charts,mtho11/hawkular-charts,hawkular/hawkular-charts,mtho11/hawkular-charts,hawkular/hawkular-charts,mtho11/hawkular-charts,tsegismont/hawkular-charts,ammendonca/hawkular-charts,hawkular/hawkular-charts,ammendonca/hawkular-charts