Merge pull request docker#231 from benileo/master

Fix overlay network example image not showing.

Author: Mano Marks

networking/concepts/06-overlay-networks.md

@@ -27,9 +27,7 @@ In this diagram we see the packet flow on an overlay network. Here are the steps
 ### Overlay Driver Internal Architecture
 The Docker Swarm control plane automates all of the provisioning for an overlay network. No VXLAN configuration or Linux networking configuration is required. Data-plane encryption, an optional feature of overlays, is also automatically configured by the overlay driver as networks are created. The user or network operator only has to define the network (`docker network create -d overlay ...`) and attach containers to that network.
 
-<span class="float-right">
 ![Overlay Network Created by Docker Swarm](./img/overlayarch.png)
-</span>
 
 During overlay network creation, Docker Engine creates the network infrastructure required for overlays on each host. A Linux bridge is created per overlay along with its associated VXLAN interfaces. The Docker Engine intelligently instantiates overlay networks on hosts only when a container attached to that network is scheduled on the host. This prevents sprawl of overlay networks where connected containers do not exist.