Add missing errors specified by OES_EGL_image_external Previously the code just silently ignored some filtering parameters for external textures, when in fact trying to set them should result in an error according to the extension specs. BUG=angleproject:1332 Change-Id: I3a691b60561638c562bc1a9780a4dcb88ac43012 Reviewed-on: https://chromium-review.googlesource.com/341441 Reviewed-by: Ian Ewell <ewell@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>