Update to docker-gen 0.7.0

Since [1] some timings seem to have changed. This caused the unit tests
to fail intermittently, from my testings especially on Ubuntu systems
(much less often on e.g. Arch).

This commit adds the `dockergen_wait_for_event` helper-function to try
and wait for the configuration to be generated by docker-gen before
continuing on with the actual tests themselves.

Additionally, at the end of every test file, all containers spun up by
the bats-tests will be stopped. This required adding the `bats-type`
label to every container started during the bats-tests.

The stopping of the containers reduces the amount of events docker-gen
has to process, thus resulting in lower wait times for the generation to
happen.

[1]: 50435652b1

test/default-host.bats

@@ -4,10 +4,7 @@ load test_helpers
 function setup {
 	# make sure to stop any web container before each test so we don't
 	# have any unexpected contaiener running with VIRTUAL_HOST or VIRUTAL_PORT set
-	CIDS=( $(docker ps -q --filter "label=bats-type=web") )
-	if [ ${#CIDS[@]} -gt 0 ]; then
-		docker stop ${CIDS[@]} >&2
-	fi
+	stop_bats_containers web
 }
 
 
@@ -20,7 +17,7 @@ function setup {
 	# WHEN nginx-proxy runs with DEFAULT_HOST set to web.bats
 	run nginxproxy $SUT_CONTAINER -v /var/run/docker.sock:/tmp/docker.sock:ro -e DEFAULT_HOST=web.bats
 	assert_success
-	docker_wait_for_log $SUT_CONTAINER 3 "Watching docker events"
+	docker_wait_for_log $SUT_CONTAINER 9 "Watching docker events"
 
 	# THEN querying the proxy without Host header → 200
 	run curl_container $SUT_CONTAINER / --head
@@ -30,3 +27,7 @@ function setup {
 	run curl_container $SUT_CONTAINER / --head --header "Host: something.I.just.made.up"
 	assert_output -l 0 $'HTTP/1.1 200 OK\r'
 }
+
+@test "[$TEST_FILE] stop all bats containers" {
+	stop_bats_containers
+}