Cherry-pick and squash changes for Gerrit on Borg support.

Commits from 'master' branch that went into this one
(most recent first):

5165e8f41a8db0772a84f97db1ad371891b044f3
Retry 'failed to lock' errors in GitPush.

d35cfc281cffb6c4b6da0c550112752c9e5783e7
Don't stomp on reserved field 'host' in HTTPSConnection.

69c556d9232e7c1aba00568aa45c535e2cfcfb30
Fix handling of '_sortkey' for subsequent change queries.

2956030b2832478a7b65888b2f2efd840899ed49
Restore scripts/gerrit.py functionality for gerrit-on-borg.

b7fa61dba5568299f1c1191198cd3921529fb7e4
Detect when a query by gerrit number fails.

685b19b7da6a61f3f896ea90848949e0a0a17fc5
Copy "host" field to retry HTTPSConnections.

00b89e5236ec7837a90d1f242f3203d90a86fef5
gob_util: Update conn.params -> conn.req_params.

86a8097e20a6cefbbdf7f70bba71b20d85306ce2
Retry requests for (presumably) transient errors.

1e8aae629519c4c109faf6bb84c53a66fe26f4c7
Retry transient GoB errors in GitPush.

976cb541fd460ad33da0bfe4d959cf253de77a32
Catch GOBError so that failing commit is reported correctly.

b545f7593f55e58a0cc49bcbd26d4532fce29b44
MultiQueryChanges should always return a list.

8600df95ba7a9e9c307fa82f2cf9739cb82b4e9d
Fix query parameters for multiple changes.

b451fc7489c18ff5c7587169eeb965640f8cba66
Capture failing http requests.

ade27ce41bb1814faf0a2ce6ffd2dc09471068db
Use email in tryjob ref name instead of username.

bd39a32381a15b99fde47f4b633f821d2f31f485
Update CHUMP detection for GoB.

03f7d96192bd2c5a9fe197d48321597e661fdabd
Use appropriate GerritHelper class.

bfeceab004ae551ad02787ce10eafc99bff3b961
Don't croak if a change's dependencies don't map to gerrit changes.

1233d305bc655346240f3f7e991c56118969c2e8
GerritPatch should handle patches with no approvals.

3d7648689ad5b5e750be4f736df5f183a03c2fb4
Disable few more tests that touch live Gerrit.

4063d984d0f7c03c003ca1a0055975adaf81f34b
Disable tests that actually submit CLs after GoB transition.

f17ec509a00e52974581a53232b137365a491677
Query changes by gerrit change number, not change-id.

ac0b8f61e8c8def0961f53900504c095d2b71963
Assorted fixes for gerrit-on-borg support.

BUG=289956
TEST=cbuildbot --remote -g <this change> -b release-R30-4537.B falco-release

Change-Id: If22d93b046061060b97b75786b01fda8d0dc6288
Reviewed-on: https://chromium-review.googlesource.com/170784
Tested-by: Vadim Shtayura <vadimsh@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>
15 files changed