kokoro: Remove code for tracking if we're in presubmit

Kokoro won't let us run apt_signer in presubmit even as a no-op, so we
have to skip it by duplicating the entire config chain in
google3. This means we no longer need any special handling of the
difference here because apt_signer, publish_apt_staging, and
publish_lxd_staging just won't run at all.

BUG=none
TEST=kokoro

Change-Id: I3d037e77f8f76762e2be78e5a23739c0cc35b0aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/containers/cros-container-guest-tools/+/2203503
Reviewed-by: Nicholas Verne <nverne@chromium.org>
Commit-Queue: Fergus Dall <sidereal@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/kokoro/apt_signer.sh b/kokoro/apt_signer.sh
index bd98273..13a77a6 100755
--- a/kokoro/apt_signer.sh
+++ b/kokoro/apt_signer.sh
@@ -36,5 +36,4 @@
                                           {} \;
 }
 
-skip_in_presubmit
 main "$@"
diff --git a/kokoro/common.sh b/kokoro/common.sh
index b2664f6..a7ee2a1 100644
--- a/kokoro/common.sh
+++ b/kokoro/common.sh
@@ -22,10 +22,3 @@
         exit 1
     fi
 }
-
-skip_in_presubmit() {
-  if [ -e "${KOKORO_ARTIFACTS_DIR}"/running_presubmits ]; then
-    echo "Skipping because this is a presubmit job"
-    exit 0
-  fi
-}
diff --git a/kokoro/presubmit.cfg b/kokoro/presubmit.cfg
deleted file mode 100644
index 6db41e6..0000000
--- a/kokoro/presubmit.cfg
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2018 The Chromium OS Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# Format: //devtools/kokoro/config/proto/build.proto
-
-build_file: "cros-container-guest-tools/kokoro/presubmit.sh"
-
-action {
-  define_artifacts {
-    regex: "running_presubmits"
-    fail_if_no_artifacts: true
-  }
-}
diff --git a/kokoro/presubmit.sh b/kokoro/presubmit.sh
deleted file mode 100755
index 6877070..0000000
--- a/kokoro/presubmit.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-# Copyright 2018 The Chromium OS Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-set -ex
-
-. "$(dirname "$0")/common.sh" || exit 1
-
-main() {
-    require_kokoro_artifacts
-
-    # This is used in other scripts to skip things like apt signing that
-    # shouldn't be done to unsubmitted code.
-    touch ${KOKORO_ARTIFACTS_DIR}/running_presubmits
-}
-
-main "$@"
diff --git a/kokoro/publish_apt_staging.sh b/kokoro/publish_apt_staging.sh
index c9bccdf..4925dac 100755
--- a/kokoro/publish_apt_staging.sh
+++ b/kokoro/publish_apt_staging.sh
@@ -21,5 +21,4 @@
     cp -r "${KOKORO_GFILE_DIR}"/apt_signed/* "${result_dir}"
 }
 
-skip_in_presubmit
 main "$@"
diff --git a/kokoro/publish_lxd_staging.sh b/kokoro/publish_lxd_staging.sh
index d723562..312e779 100755
--- a/kokoro/publish_lxd_staging.sh
+++ b/kokoro/publish_lxd_staging.sh
@@ -21,5 +21,4 @@
                                            "${result_dir}"
 }
 
-skip_in_presubmit
 main "$@"