Remove race from query finalization.

Remove race from query finalization.

BUG=

Committed: https://github.com/luci/gae/commit/5ede45528b3156419ec20f69d82c5b7a16d296a1

[dnj, 2016-04-21 22:49:15]

dnj@chromium.org changed reviewers:
+ iannucci@chromium.org

[dnj, 2016-04-21 22:49:16]

PTAL

https://chromiumcodereview.appspot.com/1910293002/diff/1/service/datastore/qu...
File service/datastore/query.go (right):

https://chromiumcodereview.appspot.com/1910293002/diff/1/service/datastore/qu...
service/datastore/query.go:51: type queryFields struct {
Why!?

Because we clone the query by copying it, meaning we inherit the (racy) error
and once state.

By splitting the RO fields from the Query-unique fields, we can copy the inner
struct (see mod) easily and avoid this situation.

[iannucci, 2016-04-22 03:36:19]

lgtm

[dnj (Google), 2016-04-22 05:23:11]

The CQ bit was checked by dnj@google.com

[commit-bot: I haz the power, 2016-04-22 05:23:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1910293002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1910293002/1

[commit-bot: I haz the power, 2016-04-22 05:28:10]

Description was changed from

==========
Remove race from query finalization.

BUG=
==========

to

==========
Remove race from query finalization.

BUG=

Committed:
https://github.com/luci/gae/commit/5ede45528b3156419ec20f69d82c5b7a16d296a1
==========

[commit-bot: I haz the power, 2016-04-22 05:28:11]

Committed patchset #1 (id:1) as
https://github.com/luci/gae/commit/5ede45528b3156419ec20f69d82c5b7a16d296a1