remove unused flag for rotated imageshaders

Bug: skia:
Change-Id: I9066ec33a9742f6937cc61ff0afafd13af809222
Reviewed-on: https://skia-review.googlesource.com/36741
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed