Vwan: Hubvnet connection related fixes

Update with review comments.
- Fix deprecation error message
- Update ChangeLog.md

Author: Shyam Dharmarajan

src/Network/Network/ChangeLog.md

@@ -44,6 +44,18 @@
 * Add `EnableDnsProxy`, 'DnsProxyNotRequiredForNetworkRule' and 'DnsServer' parameters to `AzureFirewall`
     - Updated cmdlet:
         - New-AzFirewall
+* Add deprecation warning for `HubVnetConnection` parameter in following cmdlets
+    - NewAzureRmVirtualHubCommand
+    - UpdateAzureRmVirtualHubCommand
+* Use HubVnetConnection create/update APIs instead of VirtualHub create/update APIs for following cmdlets
+    - NewAzureRmVirtualHubCommand
+    - UpdateAzureRmVirtualHubCommand
+    - NewHubVirtualNetworkConnectionCommand
+    - UpdateAzureRmHubVirtualNetworkConnectionCommand
+    - RemoveHubVirtualNetworkConnectionCommand
+* Deprecate `EnableInternetSecurity` switch parameter and instead introduce `EnableInternetSecurityFlag` boolean in
+    - NewHubVirtualNetworkConnectionCommand.
+    The flag is also made true by default for newly created connections.
 
 ## Version 2.5.0
 * Updated cmdlets to enable connection on private IP for Virtual Network Gateway.

src/Network/Network/Cortex/VirtualHub/NewAzureRmVirtualHubCommand.cs

@@ -79,7 +79,7 @@ public class NewAzureRmVirtualHubCommand : VirtualHubBaseCmdlet
         [ValidateNotNullOrEmpty]
         public string Location { get; set; }
 
-        public const String ChangeDesc = "VirtualNetworkConnection parameter is deprecated. Use AzVirtualHubVnet commands";
+        public const String ChangeDesc = "HubVnetConnection parameter is deprecated. Use *VirtualHubVnetConnection* commands";
         [CmdletParameterBreakingChange("HubVnetConnection", ChangeDescription = ChangeDesc)]
         [Parameter(
             Mandatory = false,

src/Network/Network/Cortex/VirtualHub/UpdateAzureRmVirtualHubCommand.cs

@@ -78,7 +78,7 @@ public class UpdateAzureRmVirtualHubCommand : VirtualHubBaseCmdlet
             HelpMessage = "The address space string for this virtual hub.")]
         public string AddressPrefix { get; set; }
 
-        public const String ChangeDesc = "VirtualNetworkConnection parameter is deprecated. Use AzVirtualHubVnet commands";
+        public const String ChangeDesc = "HubVnetConnection parameter is deprecated. Use *VirtualHubVnetConnection* commands";
         [CmdletParameterBreakingChange("HubVnetConnection", ChangeDescription = ChangeDesc)]
         [Parameter(
             Mandatory = false,