autodetect zabbix version

src/datasource-zabbix/partials/config.html

@@ -67,12 +67,21 @@
         Zabbix data source caches metric names in memory. Specify how often data will be updated.
       </info-popover>
     </span>
-    <input class="gf-form-input max-width-5"
+    <input class="gf-form-input max-width-7"
       type="text"
       ng-model='ctrl.current.jsonData.cacheTTL'
       placeholder="1h">
     </input>
   </div>
+
+  <div class="gf-form max-width-20">
+    <span class="gf-form-label width-12">Zabbix version</span>
+    <div class="gf-form-select-wrapper max-width-7">
+      <select class="gf-form-input" ng-model="ctrl.current.jsonData.zabbixVersion"
+        ng-options="s.value as s.name for s in ctrl.zabbixVersions">
+      </select>
+    </div>
+  </div>
 </div>
 
 <div class="gf-form-group">