Apply updates to AWS custom network install

installing/installing_aws/installing-aws-network-customizations.adoc

@@ -11,8 +11,9 @@ customizing your network configuration, your cluster can coexist with existing
 IP address allocations in your environment and integrate with existing MTU and
 VXLAN configurations.
 
-Most network configuration parameters set at installation cannot be changed
-later.
+You must set most of the network configuration parameters during installation,
+and you can modify only `kubeProxy` configuration parameters in a running
+cluster.
 
 .Prerequisites
 

modules/installation-aws-config-yaml.adoc

@@ -24,7 +24,6 @@ This sample YAML file is provided for reference only. You must obtain your
 
 [source,yaml]
 ----
-ifdef::without-networking[]
 apiVersion: v1beta3
 baseDomain: example.com <1>
 controlPlane: <2>
@@ -54,51 +53,12 @@ compute: <2>
   replicas: 5
 metadata:
   name: test-cluster <1>
+ifdef::without-networking[]
 networking:
-  clusterNetwork:
-  - cidr: 10.128.0.0/14
-    hostPrefix: 23
-  machineCIDR: 10.0.0.0/16
-  serviceNetwork:
-  - 172.30.0.0/16
-  typeType: OpenShiftSDN
-platform:
-  aws:
-    region: us-west-2 <1>
-    userTags:
-      adminContact: jdoe
-      costCenter: 7536
-pullSecret: '{"auths": ...}' <1>
-sshKey: ssh-ed25519 AAAA... <3>
 endif::[]
-
 ifdef::with-networking[]
-apiVersion: v1beta3
-baseDomain: example.com <1>
-controlPlane: <2>
-- name: master
-  platform:
-    aws:
-      zones:
-      - us-west-2a
-      - us-west-2b
-      type: m5.xlarge
-  replicas: 3
-compute: <2>
-- name: worker
-  platform:
-    aws:
-      rootVolume:
-        iops: 4000
-        size: 500
-        type: io1 <4>
-      type: c5.9xlarge
-      zones:
-      - us-west-2c
-  replicas: 5
-metadata:
-  name: test-cluster <1>
 networking: <2>
+endif::[]
   clusterNetwork:
   - cidr: 10.128.0.0/14
     hostPrefix: 23
@@ -114,7 +74,6 @@ platform:
       costCenter: 7536
 pullSecret: '{"auths": ...}' <1>
 sshKey: ssh-ed25519 AAAA... <3>
-endif::[]
 ----
 <1> Required. The installation program prompts you for this value.
 <2> If you do not provide these parameters and values, the installation program