Update datemath mock to lodash 4.

src/datasource-zabbix/specs/modules/datemath.js

@@ -91,7 +91,7 @@ export function parseDateMath(mathString, time, roundUp) {
     }
     unit = mathString.charAt(i++);
 
-    if (!_.contains(units, unit)) {
+    if (!_.includes(units, unit)) {
       return undefined;
     } else {
       if (type === 0) {

src/datasource-zabbix/specs/test-main.js

@@ -4,7 +4,7 @@
 import prunk from 'prunk';
 import {jsdom} from 'jsdom';
 import chai from 'chai';
-import sinon from 'sinon';
+// import sinon from 'sinon';
 import sinonChai from 'sinon-chai';
 import * as dateMath from './modules/datemath';