Remove cmd/gsutil image

Based on #1503

This image wrapped any image with `gsutil` in the path (typically,
`google/cloud-sdk`), and invoked it with our own custom Go wrapper.
That's unnecessary, since `gsutil` can be invoked directly as necessary,
using any image where `gsutil` is in the PATH (`google/cloud-sdk` is the
default).

This change should be entirely transparent to end users.

Operators can override the image being used if they so desire, to point
to any image that contains `gsutil`.

.ko.yaml

@@ -3,4 +3,3 @@ baseImageOverrides:
  github.com/tektoncd/pipeline/cmd/git-init: gcr.io/tekton-nightly/github.com/tektoncd/pipeline/build-base:latest
  github.com/tektoncd/pipeline/cmd/bash: bash # image must have `bash` in $PATH
  github.com/tektoncd/pipeline/cmd/entrypoint: busybox # image must have `cp` in $PATH
- github.com/tektoncd/pipeline/cmd/gsutil: google/cloud-sdk:alpine # image should have gsutil in $PATH

.ko.yaml.release

@@ -3,4 +3,3 @@ baseImageOverrides:
  github.com/tektoncd/pipeline/cmd/git-init: gcr.io/tektoncd-release/github.com/tektoncd/pipeline/build-base:latest
  github.com/tektoncd/pipeline/cmd/bash: busybox # image should have shell in $PATH
  github.com/tektoncd/pipeline/cmd/entrypoint: busybox # image should have shell in $PATH
- github.com/tektoncd/pipeline/cmd/gsutil: google/cloud-sdk:alpine # image should have gsutil in $PATH

cmd/controller/main.go

@@ -19,11 +19,10 @@ package main
 import (
  "flag"
 
- "knative.dev/pkg/injection/sharedmain"
-
  "github.com/tektoncd/pipeline/pkg/apis/pipeline"
  "github.com/tektoncd/pipeline/pkg/reconciler/pipelinerun"
  "github.com/tektoncd/pipeline/pkg/reconciler/taskrun"
+ "knative.dev/pkg/injection/sharedmain"
 )
 
 const (
@@ -44,7 +43,7 @@ var (
  "The container image containing our kubeconfig writer binary.")
  bashNoopImage = flag.String("bash-noop-image", "override-with-bash-noop:latest",
  "The container image containing bash shell")
- gsutilImage = flag.String("gsutil-image", "override-with-gsutil-image:latest",
+ gsutilImage = flag.String("gsutil-image", "google/cloud-sdk",
  "The container image containing gsutil")
  buildGCSFetcherImage = flag.String("build-gcs-fetcher-image", "gcr.io/cloud-builders/gcs-fetcher:latest",
  "The container image containing our GCS fetcher binary.")