[cipd] Add AssertOnlyDefaultSubdir.

[cipd] Add AssertOnlyDefaultSubdir.

This transitional function will end up being called by a bunch of things
in subsequent CLs.

R=vadimsh@chromium.org
BUG=663843
Review-Url: https://codereview.chromium.org/2663483002
Committed: https://github.com/luci/luci-go/commit/88f5293a10b2bcbd534e4e7a28a851b38585f3b1

[Vadim Sh., 2017-01-27 04:19:00]

lgtm

[iannucci, 2017-01-27 04:40:52]

The CQ bit was checked by iannucci@chromium.org

[commit-bot: I haz the power, 2017-01-27 04:40:53]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-27 04:53:09]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1485492052205350,
"parent_rev": "c08a552ab25cc1d8d543dbbe48f83aa0c968205b", "commit_rev":
"88f5293a10b2bcbd534e4e7a28a851b38585f3b1"}

[commit-bot: I haz the power, 2017-01-27 04:53:14]

Description was changed from

==========
[cipd] Add AssertOnlyDefaultSubdir.

This transitional function will end up being called by a bunch of things
in subsequent CLs.

R=vadimsh@chromium.org
BUG=663843
==========

to

==========
[cipd] Add AssertOnlyDefaultSubdir.

This transitional function will end up being called by a bunch of things
in subsequent CLs.

R=vadimsh@chromium.org
BUG=663843

Review-Url: https://codereview.chromium.org/2663483002
Committed:
https://github.com/luci/luci-go/commit/88f5293a10b2bcbd534e4e7a28a851b38585f3b1
==========

[commit-bot: I haz the power, 2017-01-27 04:53:15]

Committed patchset #2 (id:20001) as
https://github.com/luci/luci-go/commit/88f5293a10b2bcbd534e4e7a28a851b38585f3b1