Switch skia-perf to an attached SSD disk.
Switch skia-perf to an attached SSD disk.

BUG=skia:

Change-Id: I45b3527d1eb89df16d086364e925d7538a25094d
Reviewed-on: https://skia-review.googlesource.com/3743
Reviewed-by: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot