Fix build when the installer is re-cloned

This regression has been introduced by the previous commit, as the
relative Ptyhon dir path was not updated when the installer was
re-cloned.

Signed-off-by: Adrian Vladu <avladu@cloudbasesolutions.com>

Author: ader1990

BuildAutomation/BuildCloudbaseInitSetup.ps1

@@ -33,10 +33,8 @@ SetVCVars $VCVars $platformVCVarsRequired
 # Needed for SSH
 $ENV:HOME = $ENV:USERPROFILE
 
-$python_dir = Join-Path $repoRootPath "CloudbaseInitSetup\Python_CloudbaseInit"
 $basepath = Join-path $scriptPath "build\cloudbase-init"
 
-$ENV:PATH = "$python_dir\;$python_dir\scripts;$ENV:PATH"
 $ENV:PATH += ";$ENV:ProgramFiles (x86)\Git\bin\"
 $ENV:PATH += ";$ENV:ProgramFiles\7-zip\"
 
@@ -62,11 +60,7 @@ try
     }
     else
     {
-        if (!$InstallerDir)
-        {
-            # No path provided, so use the current installer script path.
-            $InstallerDir = (Join-Path -Path $PSScriptRoot -ChildPath ..\ -Resolve)
-        }
+        $InstallerDir = (Join-Path -Path $PSScriptRoot -ChildPath ..\ -Resolve)
         if (Test-Path $InstallerDir)
         {
             $cloudbaseInitInstallerDir = $InstallerDir
@@ -76,6 +70,8 @@ try
             throw "Installer path not present: $InstallerDir"
         }
     }
+    $python_dir = join-path $cloudbaseInitInstallerDir "CloudbaseInitSetup\Python_CloudbaseInit"
+    $ENV:PATH = "$python_dir\;$python_dir\scripts;$ENV:PATH"
 
     $python_template_dir = join-path $cloudbaseInitInstallerDir "Python$($pythonversion.replace('.', ''))_${platform}_Template"