Update Module Names in DiskEncryption setup

Change requires, since all the commands have already been changed to Az modules
Remove attempts at version sniffing, because there are no old versions of the Az.* modules

Author: Jaykul

src/Compute/Compute/Extension/AzureDiskEncryption/Scripts/AzureDiskEncryptionPreRequisiteSetup.ps1

@@ -1,5 +1,5 @@
-#Requires -Module AzureRM.Resources
-#Requires -Module AzureRM.KeyVault
+#Requires -Module Az.Resources
+#Requires -Module Az.KeyVault
 
 Param(
   [Parameter(Mandatory = $true, 
@@ -52,8 +52,6 @@ $ErrorActionPreference = "Stop"
 # Section2:  Create AAD app if encryption is enabled using AAD. Fill in $aadClientSecret variable if AAD app was already created.
 ####################################################################################################################################
 
-    $azureResourcesModule = Get-Module 'AzureRM.Resources';
-
     if($aadAppName)
     {
         # Check if AAD app with $aadAppName was already created
@@ -68,15 +66,8 @@ $ErrorActionPreference = "Stop"
             $aadClientSecret = [Guid]::NewGuid().ToString();
             Write-Host "Creating new AAD application ($aadAppName)";
 
-            if($azureResourcesModule.Version.Major -ge 5)
-            {
-                $secureAadClientSecret = ConvertTo-SecureString -String $aadClientSecret -AsPlainText -Force;
-                $ADApp = New-AzADApplication -DisplayName $aadAppName -HomePage $defaultHomePage -IdentifierUris $identifierUri  -StartDate $now -EndDate $oneYearFromNow -Password $secureAadClientSecret;
-            }
-            else
-            {
-                $ADApp = New-AzADApplication -DisplayName $aadAppName -HomePage $defaultHomePage -IdentifierUris $identifierUri  -StartDate $now -EndDate $oneYearFromNow -Password $aadClientSecret;
-            }
+	    $secureAadClientSecret = ConvertTo-SecureString -String $aadClientSecret -AsPlainText -Force;
+	    $ADApp = New-AzADApplication -DisplayName $aadAppName -HomePage $defaultHomePage -IdentifierUris $identifierUri  -StartDate $now -EndDate $oneYearFromNow -Password $secureAadClientSecret;
 
             $servicePrincipal = New-AzADServicePrincipal -ApplicationId $ADApp.ApplicationId;
             $SvcPrincipals = (Get-AzADServicePrincipal -SearchString $aadAppName);
@@ -250,12 +241,6 @@ foreach($vm in $allVMs)
     }
     else
     {
-        if($azureResourcesModule.Version.Major -lt 6)
-        {
-            Write-Error "Please specify AAD application details, or install AzurePowershell version 6.0.0.0 or above to use AzureDiskEncryption without AAD";
-            return;
-        }
-
         if(-not $kek)
         {
             Set-AzVMDiskEncryptionExtension -ResourceGroupName $vm.ResourceGroupName -VMName $vm.Name -DiskEncryptionKeyVaultUrl $diskEncryptionKeyVaultUrl -DiskEncryptionKeyVaultId $keyVaultResourceId -VolumeType 'All';