fetch: Fix GCLIENT_PY3 on Windows

Bug: 939847
Change-Id: Ic5f87c7423ab72086ca928fecc15ed60408fbedd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1900165
Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

fetch.bat

@@ -13,7 +13,7 @@ set PATH=%PATH%;%~dp0
 
 :: Defer control.
 IF "%GCLIENT_PY3%" == "1" (
-  vpython3 "%~dp0\fetch.py" %*y
+  vpython3 "%~dp0\fetch.py" %*
 ) ELSE (
   vpython "%~dp0\fetch.py" %*
 )