Move --eventlog-endpoint out of isolateFlags.

Move --eventlog-endpoint out of isolateFlags.

The batcharchive subcommand instantiates multiple isolateFlag structs per
invocation. We want only a single eventlog endpoint per invocation. So, this CL
moves the eventlog-endpoint flag out of isolateFlags, into its own struct that
can be used directly from the batchArchiveRun, expArchiveRun and ArchiveRun
structs.

BUG=727985
Review-Url: https://codereview.chromium.org/2921393002
Committed: https://github.com/luci/luci-go/commit/98bc6697c7d6ffb6dd445180d5cd0d8426aab28d

[mcgreevy, 2017-06-06 03:52:11]

mcgreevy@chromium.org changed reviewers:
+ tansell@chromium.org

[mithro, 2017-06-06 06:48:30]

lgtm

[mcgreevy, 2017-06-06 06:49:36]

The CQ bit was checked by mcgreevy@chromium.org

[commit-bot: I haz the power, 2017-06-06 06:49:45]

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, 2017-06-06 06:55:29]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1496731776305180, "parent_rev":
"e4c28c843ad9c957d7d3bde039ca8ccfe033b5de", "commit_rev":
"98bc6697c7d6ffb6dd445180d5cd0d8426aab28d"}

[commit-bot: I haz the power, 2017-06-06 06:55:32]

Description was changed from

==========
Move --eventlog-endpoint out of isolateFlags.

The batcharchive subcommand instantiates multiple isolateFlag structs per
invocation. We want only a single eventlog endpoint per invocation. So, this CL
moves the eventlog-endpoint flag out of isolateFlags, into its own struct that
can be used directly from the batchArchiveRun, expArchiveRun and ArchiveRun
structs.

BUG=727985
==========

to

==========
Move --eventlog-endpoint out of isolateFlags.

The batcharchive subcommand instantiates multiple isolateFlag structs per
invocation. We want only a single eventlog endpoint per invocation. So, this CL
moves the eventlog-endpoint flag out of isolateFlags, into its own struct that
can be used directly from the batchArchiveRun, expArchiveRun and ArchiveRun
structs.

BUG=727985

Review-Url: https://codereview.chromium.org/2921393002
Committed:
https://github.com/luci/luci-go/commit/98bc6697c7d6ffb6dd445180d5cd0d8426aab28d
==========

[commit-bot: I haz the power, 2017-06-06 06:55:33]

Committed patchset #1 (id:1) as
https://github.com/luci/luci-go/commit/98bc6697c7d6ffb6dd445180d5cd0d8426aab28d