AWS Migration

This is the code at the time of the AWS migration.  This is the last code to
run in the SCL3 datacenter, except for a follow-on commit that turned on
MAINTENANCE_MODE by default.

Merge pull request mdn#2850 from jezdez/bug1084003-2

fix bug 1084003 - repair migrations after attachment split

Merge pull request mdn#2737 from groovecoder/attachments-app-1057286

bug 1057286 - custom chief logic for attachments migrations cleanup

Updated test instructions in MOTD and travis config.

push by lorchard_j

push by groovecoder

push by dwalsh

Merge pull request mdn#475 from darkwing/tags-spaces-776978

fix bug 776978 - Quote all tags to avoid space issues

Merge pull request mdn#457 from groovecoder/migrate-demos-773480

bug 773480 - only replace tagged items records; not tags

fix bug 777837: Separate apps landing page from waffle switch for app…

…s promo on home page