Revert "Add luci-go tool to be fetched via CIPD"

This reverts commit 3bcc71d83f6d9af93a7408fbea34f6d5f0185c03.

Reason for revert: appears to break official builds due to how the cipd variable is flattened.

Original change's description:
> Add luci-go tool to be fetched via CIPD
>
> Do not remove the adhoc mechanism on GCS that predates CIPD yet, as the recipes
> need to be updated.
>
> Change analyze to not ignore changes to isolate.
>
> R=​tandrii@chromium.org
>
> Bug: 851596
> Change-Id: Ic068db83dea4c3a0f17b55181de523b16c9838a5
> Reviewed-on: https://chromium-review.googlesource.com/1097623
> Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
> Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569688}

TBR=maruel@chromium.org,tandrii@chromium.org,ehmaldonado@chromium.org,jbudorick@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

No-Presubmit: true
Bug: 851596
Change-Id: I3717c6b0ebf68b08908037850d122727e41bf192
Reviewed-on: https://chromium-review.googlesource.com/1112823
Commit-Queue: John Budorick <jbudorick@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#569938}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 0c062061326cd05a1ab884e5b2d6e03e2b79f215
diff --git a/.gitignore b/.gitignore
index 99085c5..06e9510 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,3 @@
-/isolate
-/isolate.exe
 /linux64/isolate
 /mac64/isolate
 /win64/isolate.exe
diff --git a/OWNERS b/OWNERS
index 8b03e48..3bcc77d 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,3 +1,5 @@
+djd@chromium.org
 maruel@chromium.org
 tandrii@chromium.org
+tansell@chromium.org
 vadimsh@chromium.org
diff --git a/README.md b/README.md
index 5cb0ddf..f53bec1 100644
--- a/README.md
+++ b/README.md
@@ -2,4 +2,9 @@
 
 Contains executable built out of
 https://chromium.googlesource.com/infra/luci/luci-go/+/master/client/cmd
-Mapped through CIPD.
+
+The binaries are retrieved from the following builders:
+
+- mac64: http://build.chromium.org/p/chromium.infra/builders/infra-continuous-mac-10.10-64/
+- linux64: http://build.chromium.org/p/chromium.infra/builders/infra-continuous-precise-64/
+- win64: http://build.chromium.org/p/chromium.infra/builders/infra-continuous-win-64/