make,integration-dind: try to remove dpy-dind

b/c if test fails, dpy-dind is left running and integration-dind target
will refuse to start and you need to manually force-remove the container
Signed-off-by: Tomas Tomecek <ttomecek@redhat.com>

Makefile

@@ -31,6 +31,7 @@ integration-test-py3: build-py3
 	docker run -v /var/run/docker.sock:/var/run/docker.sock docker-py3 py.test tests/integration
 
 integration-dind: build build-py3
+	docker rm -vf dpy-dind || :
 	docker run -d --name dpy-dind --env="DOCKER_HOST=tcp://localhost:2375" --privileged dockerswarm/dind:1.9.0 docker -d -H tcp://0.0.0.0:2375
 	docker run --env="DOCKER_HOST=tcp://docker:2375" --link=dpy-dind:docker docker-py py.test tests/integration
 	docker run --env="DOCKER_HOST=tcp://docker:2375" --link=dpy-dind:docker docker-py3 py.test tests/integration