fiddle: Fix JSON output logic.

BUG=skia:

Change-Id: Ia17b8328f692881282be15afa5e7f661ddc83318
Reviewed-on: https://skia-review.googlesource.com/8388
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
1 file changed