Make TestLogsAPIUntil less flaky

Commit ee594dcb7d42f95048c9047d86c61447243db3cd removed the
`sleep 0.5` from this test, because sleep has a full-second
precision. However, in some cases, all three log-entries
are output at the same time, causing the `--until` filter
to fail.

This patch adds back a `sleep`, but uses 1 second instead.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
diff --git a/integration-cli/docker_api_logs_test.go b/integration-cli/docker_api_logs_test.go
index 41164df..ef1e77d 100644
--- a/integration-cli/docker_api_logs_test.go
+++ b/integration-cli/docker_api_logs_test.go
@@ -151,7 +151,7 @@
 
 func (s *DockerSuite) TestLogsAPIUntil(c *check.C) {
 	name := "logsuntil"
-	dockerCmd(c, "run", "--name", name, "busybox", "/bin/sh", "-c", "for i in $(seq 1 3); do echo log$i; done")
+	dockerCmd(c, "run", "--name", name, "busybox", "/bin/sh", "-c", "for i in $(seq 1 3); do echo log$i; sleep 1; done")
 
 	client, err := request.NewClient()
 	if err != nil {