build: migrate to flakybot (googleapis#140)

Author: JustinBeckwith

.kokoro/test-samples.sh

@@ -87,11 +87,11 @@ for file in samples/**/requirements.txt; do
     python3.6 -m nox -s "$RUN_TESTS_SESSION"
     EXIT=$?
 
-    # If this is a periodic build, send the test log to the Build Cop Bot.
-    # See https://github.com/googleapis/repo-automation-bots/tree/master/packages/buildcop.
+    # If this is a periodic build, send the test log to the FlakyBot.
+    # See https://github.com/googleapis/repo-automation-bots/tree/master/packages/flakybot.
     if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
-      chmod +x $KOKORO_GFILE_DIR/linux_amd64/buildcop
-      $KOKORO_GFILE_DIR/linux_amd64/buildcop
+      chmod +x $KOKORO_GFILE_DIR/linux_amd64/flakybot
+      $KOKORO_GFILE_DIR/linux_amd64/flakybot
     fi
 
     if [[ $EXIT -ne 0 ]]; then

.kokoro/trampoline_v2.sh

@@ -159,7 +159,7 @@ if [[ -n "${KOKORO_BUILD_ID:-}" ]]; then
 	"KOKORO_GITHUB_COMMIT"
 	"KOKORO_GITHUB_PULL_REQUEST_NUMBER"
 	"KOKORO_GITHUB_PULL_REQUEST_COMMIT"
-	# For Build Cop Bot
+	# For FlakyBot
 	"KOKORO_GITHUB_COMMIT_URL"
 	"KOKORO_GITHUB_PULL_REQUEST_URL"
     )