use guids for download jobs

extdep/getstuff.bat

@@ -24,10 +24,10 @@ set eth_version=%2
 cd download
 
 if not exist %eth_name%-%eth_version%.tar.gz (
-	bitsadmin /cancel %eth_name%-%eth_version%.tar.gz
-	bitsadmin /create %eth_name%-%eth_version%.tar.gz
-	bitsadmin /transfer %eth_name%-%eth_version%.tar.gz /download /priority normal %eth_server%/%eth_name%-%eth_version%.tar.gz %cd%\%eth_name%-%eth_version%.tar.gz
-	bitsadmin /cancel %eth_name%-%eth_version%.tar.gz
+	for /f "tokens=2 delims={}" %%g in ('bitsadmin /create %eth_name%-%eth_version%.tar.gz') do (
+		bitsadmin /transfer {%%g} /download /priority normal %eth_server%/%eth_name%-%eth_version%.tar.gz %cd%\%eth_name%-%eth_version%.tar.gz
+		bitsadmin /cancel {%%g}
+	)
 )
 if not exist %eth_name%-%eth_version% cmake -E tar -zxvf %eth_name%-%eth_version%.tar.gz
 cmake -E copy_directory %eth_name%-%eth_version% ..\install\windows
@@ -35,3 +35,4 @@ cmake -E copy_directory %eth_name%-%eth_version% ..\install\windows
 cd ..
 
 goto :EOF
+