EAGLESIX-2651: Sum: use triple equality check

lib/pipeline/accumulators/SumAccumulator.js

@@ -15,7 +15,7 @@ var SumAccumulator = module.exports = function SumAccumulator() {
 
 proto.processInternal = function processInternal(input, merging) {
 	// do nothing with non numeric types
-	if (typeof input != "number"){
+	if (typeof input !== "number"){
 		if (input !== undefined && input !== null) { //NOTE: DEVIATION FROM MONGO: minor fix for 0-like values
 			this.isNumber = false;
 		}