Remove pre-attachment of stencil buffers

Change-Id: I4ef555a2b36cf3a0ec74e0ecf7e8ab4f8779df3e
Reviewed-on: https://skia-review.googlesource.com/49740
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
6 files changed