all: make tests run on trybots

- storage/db/dbtest, storage/cmd/reindex: hide cloud SQL behind a build tag
  (run go test -tags cloud -cloud to run tests)
- analysis/appengine, storage/appengine: hide behind appengine build tag
  (automatically supplied by goapp)
- vendor: used govendor to import non-x non-appengine dependencies

Change-Id: Ia5590599e7191ab3427618204fab7d2cec907579
Run-TryBot: Quentin Smith <>
Reviewed-by: Brad Fitzpatrick <>
Reviewed-by: Russ Cox <>
145 files changed