Treat no index in msearch as empty instead of global

Prior to this, if you were to pass an empty index list to the search
fetch strategy in courier, kibana would perform an msearch on all
indexes in elasticsearch. This commit implements the desired behavior
that no defined index list means there are no indexes to query, and thus
is treated like an empty response.

src/ui/public/courier/fetch/strategy/__tests__/search.js

@@ -0,0 +1,63 @@
+describe('ui/courier/fetch/strategy/search', () => {
+  const _ = require('lodash');
+  const sinon = require('auto-release-sinon');
+  const expect = require('expect.js');
+  const ngMock = require('ngMock');
+
+  let Promise;
+  let $rootScope;
+  let search;
+  let reqsFetchParams;
+
+  beforeEach(ngMock.module('kibana'));
+
+  beforeEach(ngMock.inject((Private, $injector) => {
+    Promise = $injector.get('Promise');
+    $rootScope = $injector.get('$rootScope');
+    search = Private(require('ui/courier/fetch/strategy/search'));
+    reqsFetchParams = [
+      {
+        index: ['logstash-123'],
+        type: 'blah',
+        search_type: 'blah2',
+        body: 'hm this is the body'
+      }
+    ];
+  }));
+
+  describe('#clientMethod', () => {
+    it('is msearch', () => {
+      expect(search.clientMethod).to.equal('msearch');
+    });
+  });
+
+  describe('#reqsFetchParamsToBody()', () => {
+    context('when indexList is not empty', () => {
+      it('includes the index', () => {
+        let value;
+        search.reqsFetchParamsToBody(reqsFetchParams).then(val => value = val);
+        $rootScope.$apply();
+        expect(_.includes(value, '"index":["logstash-123"]')).to.be(true);
+      });
+    });
+
+    context('when indexList is empty', () => {
+      beforeEach(() => reqsFetchParams[0].index = []);
+
+      it('explicitly negates any indexes', () => {
+        let value;
+        search.reqsFetchParamsToBody(reqsFetchParams).then(val => value = val);
+        $rootScope.$apply();
+        expect(_.includes(value, '"index":["-*"]')).to.be(true);
+      });
+    });
+  });
+
+  describe('#getResponses()', () => {
+    it('returns the `responses` property of the given arg', () => {
+      const responses = [{}];
+      const returned = search.getResponses({ responses });
+      expect(returned).to.be(responses);
+    });
+  });
+});

src/ui/public/courier/fetch/strategy/search.js

@@ -24,6 +24,9 @@ define(function (require) {
             return indexList.toIndexList(timeBounds.min, timeBounds.max);
           })
           .then(function (indexList) {
+            if (_.isArray(indexList) && indexList.length === 0) {
+              indexList.push('-*');
+            }
             return angular.toJson({
               index: indexList,
               type: fetchParams.type,