Remove extraneous comma in printf vargs

Bug: skia:
Change-Id: I5e40d9c334c959e1a777251e1ac25f3703f9b7f9
Reviewed-on: https://skia-review.googlesource.com/c/159327
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
1 file changed