Add Beignet to Linux setup.
Add Beignet to Linux setup.

Bug: skia:8081
Change-Id: I8d99fb700b1332c8640a0854b62e17ff0211fc0c
Reviewed-on: https://skia-review.googlesource.com/137707
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>
Commit-Queue: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@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