add obsolete message

Author: azdevxps

src/ResourceManager/Network/Commands.Network/VirtualNetwork/Peering/AddAzureVirtualNetworkPeeringCommand.cs

@@ -52,6 +52,7 @@ public class AddAzureVirtualNetworkPeeringCommand : VirtualNetworkPeeringBase
             HelpMessage = "Flag to allow the forwarded traffic from the VMs in the remote virtual network")]
         public SwitchParameter AllowForwardedTraffic { get; set; }
 
+        [Obsolete("Add-AzureRmVirtualNetworkPeering: -AlloowGatewayTransit will be removed in an upcoming breaking change release.  Please start using -AllowGatewayTransit to avoid breaking scripts.")]
         [Alias("AlloowGatewayTransit")]
         [Parameter(
             Mandatory = false,
@@ -95,7 +96,9 @@ private PSVirtualNetworkPeering AddVirtualNetworkPeering()
             }
 
             vnetPeering.AllowVirtualNetworkAccess = !this.BlockVirtualNetworkAccess.IsPresent;
+#pragma warning disable CS0618
             vnetPeering.AllowGatewayTransit = this.AllowGatewayTransit;
+#pragma warning restore CS0618
             vnetPeering.AllowForwardedTraffic = this.AllowForwardedTraffic;
             vnetPeering.UseRemoteGateways = this.UseRemoteGateways;