DVCSMP-3664 Fix NPE in zigbee metering plug (#11345)

Author: greens

devicetypes/smartthings/zigbee-metering-plug.src/zigbee-metering-plug.groovy

@@ -85,13 +85,13 @@ def parse(String description) {
 
         attrData.each {
                 def map = [:]
-                if (it.clusterInt == zigbee.SIMPLE_METERING_CLUSTER && it.attrInt == ATTRIBUTE_HISTORICAL_CONSUMPTION) {
+                if (it.value && it.clusterInt == zigbee.SIMPLE_METERING_CLUSTER && it.attrInt == ATTRIBUTE_HISTORICAL_CONSUMPTION) {
                         log.debug "power"
                         map.name = "power"
                         map.value = zigbee.convertHexToInt(it.value)/powerDiv
                         map.unit = "W"
                 }
-                else if (it.clusterInt == zigbee.SIMPLE_METERING_CLUSTER && it.attrInt == ATTRIBUTE_READING_INFO_SET) {
+                else if (it.value && it.clusterInt == zigbee.SIMPLE_METERING_CLUSTER && it.attrInt == ATTRIBUTE_READING_INFO_SET) {
                         log.debug "energy"
                         map.name = "energy"
                         map.value = zigbee.convertHexToInt(it.value)/energyDiv