integration-cli: pull busybox before running

Make sure the busybox image is ready to be used when running the cli
integration tests.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Upstream-commit: f7ae3a1381fdc53042bebec085bb3f108bc05da3
Component: engine

components/engine/hack/make/test-integration-cli

@@ -19,6 +19,10 @@ fi
 
 docker -d -D -p $DEST/docker.pid &> $DEST/docker.log &
 
+# pull the busybox image before running the tests
+sleep 2
+docker pull busybox
+
 bundle_test_integration_cli 2>&1 \
 	| tee $DEST/test.log