Update config examples for 0.7.0

The config examples used incorrect logger configuration and were difficult to
read. This change fixes them to use 0.7.0 logger configuration, defaults to
debug to make it easier for new users to understand why their cluster won't
start up, and adjust the formatting to make for easier readability.

README.md

@@ -256,32 +256,31 @@ The following configuration example enables the autoscaling based cluster discov
 
 ```erlang
 [
- {rabbit, [
-           {log_levels, [{autocluster, info}, {connection, info}]}
-                        ]},
-                         {autocluster, [
-                                        {backend, aws},
-                                                  {aws_autoscaling, true},
-                                                  {aws_ec2_region, "us-west-2"}
-                                                  ]}
-                                                   ].
+  {autocluster, [
+    {autocluster_log_level, debug},
+    {backend, aws},
+    {aws_autoscaling, true},
+    {aws_ec2_region, "us-west-2"}
+  ]}
+].
 ```
 
 For non-autoscaling group based clusters, the following configuration demonstrates how to limit EC2 instances in the cluster to nodes with the tags ``region=us-west-2`` and ``service=rabbitmq``. It also specifies the AWS access key and AWS secret key.
 
 ```erlang
 [
- {rabbit, [
-           {log_levels, [{autocluster, info}, {connection, info}]}
-                        ]},
-                         {autocluster, [
-                                        {backend, aws},
-                                                  {aws_ec2_tags, [{"region", "us-west-2"}, {"service", "rabbitmq"}]},
-                                                  {aws_ec2_region, "us-east-1"},
-                                                  {aws_access_key, "AKIDEXAMPLE"},
-                                                  {aws_secret_key, "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY"}
-                                                  ]}
-                                                   ].
+  {autocluster, [
+    {autocluster_log_level, debug},
+    {backend, aws},
+    {aws_ec2_tags, [
+      {"region", "us-west-2"},
+      {"service", "rabbitmq"}
+    ]},
+    {aws_ec2_region, "us-east-1"},
+    {aws_access_key, "AKIDEXAMPLE"},
+    {aws_secret_key, "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY"}
+  ]}
+].
 ```
 
 When using environment variables, the tags must be provided in JSON format: