Ensure no_src benchmarks run with soft_deletes disabed

[1] makes `index.soft_deletes.enabled: True` the index
default. soft_deletes require the doc source stored and if source gets
explicitly disabled during index creation, Elasticsearch will use a
`_recovery_source` [2] instead to store the source.

To allow the execution of no_src benchmarks, explicitly disable
soft_deletes for the specific combinations.

[1] elastic@51800de
[2] elastic#31106

Relates elastic#90

Author: dliappis

night_rally/resources/tracks.json

@@ -310,6 +310,11 @@
         "charts": ["indexing"],
         "challenge": "append-no-conflicts-index-only",
         "track-params": {
+          "index_settings": {
+            "index.number_of_shards": 5,
+            "index.number_of_replicas": 0,
+            "index.soft_deletes.enabled": false
+          },
           "source_enabled": false
         },
         "car": "4gheap"
@@ -346,6 +351,11 @@
         "charts": ["indexing"],
         "challenge": "append-index-only-with-ingest-pipeline",
         "track-params": {
+          "index_settings": {
+            "index.number_of_shards": 5,
+            "index.number_of_replicas": 0,
+            "index.soft_deletes.enabled": false
+          },
           "source_enabled": false,
           "ingest_pipeline": "grok"
         },

tests/night_rally_test.py

@@ -242,6 +242,51 @@ def test_run_adhoc_benchmark(self, mocked_wait_until_port_is_free):
             system_call.calls
         )
 
+    @mock.patch('night_rally.night_rally.wait_until_port_is_free', return_value=True)
+    def test_run_track_with_soft_deletes_and_src_disabled(self, mocked_wait_until_port_is_free):
+        system_call = RecordingSystemCall(return_value=False)
+        self.maxDiff=None
+        tracks = [
+            {
+                "track": "http_logs",
+                "configurations": [
+                    {
+                        "name": "http_logs-no-src-1node",
+                        "challenge": "append-no-conflicts-index-only",
+                        "car": "4gheap",
+                        "track-params": {
+                            "index_settings": {
+                                "index.number_of_shards": 5,
+                                "index.number_of_replicas": 0,
+                                "index.soft_deletes.enabled": False
+                            },
+                            "source_enabled": False
+                        }
+                    }
+                ]
+            }
+        ]
+
+        start_date = datetime.datetime(2016, 1, 1)
+        params = [night_rally.StandardParams("nightly", start_date, 8, {"env": "bare"})]
+        cmd = night_rally.NightlyCommand(params, start_date)
+        night_rally.run_rally(tracks, ["localhost"], cmd, skip_ansible=True, system=system_call)
+        self.assertEqual(1, len(system_call.calls))
+        self.assertEqual(
+            [
+                "rally --skip-update --configuration-name=\"nightly\" --quiet --target-host=\"localhost:39200\" "
+                "--effective-start-date=\"2016-01-01 00:00:00\" --track=\"http_logs\" "
+                "--challenge=\"append-no-conflicts-index-only\" --car=\"4gheap\" --client-options=\"timeout:240\" "
+                "--user-tag=\"env:bare,name:http_logs-no-src-1node\" --runtime-jdk=\"8\" "
+                "--track-params=\"{\\\"index_settings\\\": {\\\"index.number_of_shards\\\": 5, "
+                "\\\"index.number_of_replicas\\\": 0, \\\"index.soft_deletes.enabled\\\": false}, "
+                "\\\"source_enabled\\\": false}\" "
+                "--pipeline=\"from-sources-complete\" "
+                "--revision=\"@2016-01-01T00:00:00Z\""            ]
+            ,
+            system_call.calls
+        )
+
     @mock.patch('night_rally.night_rally.wait_until_port_is_free', return_value=True)
     def test_run_release_benchmark_without_plugins(self, mocked_wait_until_port_is_free):
         system_call = RecordingSystemCall(return_value=False)