Update ansible with new scheduler instructions (#5202)

* Update ansible/scheduler instructions

Add instructions to add configuration for akka dispatcher, add complete file paths in two places

* Change lease service to PinnedDispatcher

Author: hunhoffe

ansible/README.md

@@ -156,7 +156,7 @@ It will run one more component called "scheduler" and ETCD.
 #### Configure service providers for the scheduler
 You can update service providers for the scheduler as follows. 
 
-**common/scala/src/main/resources**
+**common/scala/src/main/resources/reference.conf**
 ```
 whisk.spi {
   ArtifactStoreProvider = org.apache.openwhisk.core.database.CouchDbStoreProvider
@@ -176,10 +176,24 @@ whisk.spi {
 .
 ```
 
+#### Configure akka dispatcher for the scheduler
+Add a new dispatcher entry as follows.
+
+**common/scala/src/main/resources/reference.conf**
+```
+  lease-service-dispatcher {
+    executor = "thread-pool-executor"
+    type = PinnedDispatcher
+  }
+.
+.
+.
+```
+
 #### Enable the scheduler
 - Make sure you enable the scheduler by configuring `scheduler_enable`.
 
-**ansible/environments/local/group_vars**
+**ansible/environments/local/group_vars/all**
 ```yaml
 scheduler_enable: true
 ```