C#: Correctly propagate exit code in autobuild.cmd

Author: hvitved

csharp/tools/autobuild.cmd

@@ -1,9 +1,7 @@
 @echo off
-SETLOCAL EnableDelayedExpansion
 
 rem The autobuilder is already being traced
 set CODEQL_AUTOBUILDER_CSHARP_NO_INDEXING=true
 
-type NUL && "%CODEQL_EXTRACTOR_CSHARP_ROOT%/tools/%CODEQL_PLATFORM%/Semmle.Autobuild.CSharp.exe" || exit /b %ERRORLEVEL%
-
-ENDLOCAL
+type NUL && "%CODEQL_EXTRACTOR_CSHARP_ROOT%/tools/%CODEQL_PLATFORM%/Semmle.Autobuild.CSharp.exe"
+IF %ERRORLEVEL% NEQ 0 exit /b %ERRORLEVEL%