Merge pull request #5167 from Azure/maddieclayton-patch-2

Update example for VirtualNetworkGateway so it can be run

Author: markcowl

src/ResourceManager/Network/Commands.Network/help/New-AzureRmVirtualNetworkGateway.md

@@ -72,7 +72,7 @@ You can also choose to include other features like BGP and Active-Active.
 ### 1: Create a Virtual Network Gateway
 ```
 New-AzureRmResourceGroup -Location "UK West" -Name "vnet-gateway"
-New-AzureRMVirtualNetworkSubnetConfig -Name 'gatewaysubnet' -AddressPrefix '10.254.0.0/27'
+$subnet = New-AzureRMVirtualNetworkSubnetConfig -Name 'gatewaysubnet' -AddressPrefix '10.254.0.0/27'
 
 $ngwpip = New-AzureRMPublicIpAddress -Name ngwpip -ResourceGroupName "vnet-gateway" -Location "UK West" -AllocationMethod Dynamic
 $vnet = New-AzureRmVirtualNetwork -AddressPrefix "10.254.0.0/27" -Location "UK West" -Name vnet-gateway -ResourceGroupName "vnet-gateway" -Subnet $subnet