Fix build.bat broken by 3c3ca70f.

compile.bat

@@ -90,6 +90,7 @@ if errorlevel 1 goto failed
 
 echo Success!
 
+if "%1"=="issigtool" goto exit
 rem  Sign using user's private key - will be overwritten if called by build.bat
 call .\issig.bat sign Files\ISCmplr.dll Files\ISPP.dll Files\Setup.e32 Files\SetupLdr.e32
 if errorlevel 1 goto failed