Generalize NewConfig-IsValid to Config-IsValid.

The updater should also check if an existing configuration that won't be
updated validates correctly with newer service binaries and stop the
process of updating if the check fails.

Refers to #28

Updater/Update-Service.ps1

@@ -306,7 +306,7 @@ function NewConfig-Available {
 }
 
 
-function NewConfig-IsValid {
+function Config-IsValid {
     # Check if the new configuration provided at $UpdPathConfig validates with
     # the appropriate "AutoTxConfigTest" binary (either the existing one in the
     # service installation directory (if the service binaries won't be updated)
@@ -319,19 +319,23 @@ function NewConfig-IsValid {
     Param (
         [Parameter(Mandatory=$True)]
         [ValidateScript({(Test-Path $_ -PathType Leaf)})]
-        [String]$ConfigTest
+        [String]$ConfigTest,
+
+        [Parameter(Mandatory=$True)]
+        [ValidateScript({(Test-Path $_ -PathType Container)})]
+        [String]$ConfigPath
     )
-    Write-Verbose "Running [$($ConfigTest) $($UpdPathConfig)]..."
-    $Summary = & $ConfigTest $UpdPathConfig
+    Write-Verbose "Running [$($ConfigTest) $($ConfigPath)]..."
+    $Summary = & $ConfigTest $ConfigPath
     $Ret = $?
     # pipe through Out-String to preserve line breaks:
     $Summary = "$("=" * 80)`n$($Summary | Out-String)`n$("=" * 80)"
 
     if ($Ret) {
-        Log-Debug "Successfully validated new configuration files!`n$($Summary)"
+        Log-Debug "Validated config files at [$($ConfigPath)]!`n$($Summary)"
         Return $Ret, $Summary
     }
-    Log-Error "Config at [$($UpdPathConfig)] failed validation!`n$($Summary)"
+    Log-Error "Config at [$($ConfigPath)] FAILED VALIDATION!`n$($Summary)"
     Return $Ret, $Summary
 }