Small fix to graphiteDatasource and sending cacheTimeout undefined, reintroduced…

Small fix to graphiteDatasource and sending cacheTimeout undefined, reintroduced this bug yesterday, added unit test so it should not appear again

src/app/services/graphite/graphiteDatasource.js

@@ -251,7 +251,9 @@ function (angular, _, $, config, kbn, moment) {
 
       _.each(options, function (value, key) {
         if ($.inArray(key, graphite_options) === -1) { return; }
-        clean_options.push(key + "=" + encodeURIComponent(value));
+        if (value) {
+          clean_options.push(key + "=" + encodeURIComponent(value));
+        }
       });
 
       return clean_options;

src/test/specs/graphiteDatasource-specs.js

@@ -18,7 +18,7 @@ define([
       var query = {
         range: { from: 'now-1h', to: 'now' },
         targets: [{ target: 'prod1.count' }, {target: 'prod2.count'}],
-        maxDataPoints: 500
+        maxDataPoints: 500,
       };
 
       var response = [{ target: 'prod1.count', points: [[10, 1], [12,1]], }];
@@ -46,6 +46,11 @@ define([
         expect(params).to.contain('until=now');
       });
 
+      it('should exclude undefined params', function() {
+        var params = request.split('&');
+        expect(params).to.not.contain('cacheTimeout=undefined');
+      });
+
       it('should return series list', function() {
         expect(results.data.length).to.be(1);
         expect(results.data[0].target).to.be('prod1.count');