Sort MB configs in mb_config.pyl.
Sort MB configs in mb_config.pyl.

Life will probably be easier down the road if the order in which the
builders appear in the MB file matches the order they appear in
the /builders pages on the bots. So, this CL re-sorts mb_config.pyl
to match the buildbot ordering.

This CL also sorts the 'configs' dict alphabetically for ease of
maintenance there as well.

R=brettw@chromium.org
BUG=481692

Review URL: https://codereview.chromium.org/1275193004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#342298}

CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend