Fix directory creation in skqp app

Bug: skia:
Change-Id: Id26832ccce7d09d3d3d640bcdd11a424f18943f7
Reviewed-on: https://skia-review.googlesource.com/92682
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
5 files changed