Correct documentation mistake

`ssh-agent -L` will result in `unknown option -- L`

Author: ngbinh

README.md

@@ -194,7 +194,7 @@ Use `deis run` to execute one-off commands and explore the deployed container.
 Common issues that users have run into when provisioning Deis are detailed below.
 
 #### When running a `make` action - 'Failed initializing SSH client: ssh: handshake failed: ssh: unable to authenticate'
-Did you remember to add your SSH key to the ssh-agent? `ssh-agent -L` should list the key you used to provision the servers. If it's not there, `ssh-add -K /path/to/your/key`.
+Did you remember to add your SSH key to the ssh-agent? `ssh-add -L` should list the key you used to provision the servers. If it's not there, `ssh-add -K /path/to/your/key`.
 
 #### When running a `make` action - 'All the given peers are not reachable (Tried to connect to each peer twice and failed)'
 The most common cause of this issue is that a [new discovery URL](https://discovery.etcd.io/new) wasn't generated and updated in [contrib/coreos/user-data](contrib/coreos/user-data) before the cluster was launched. Each Deis cluster must have a unique discovery URL, else there will be entries for old hosts that etcd will try and fail to connect to. Destroy and relaunch the cluster, ensuring to use a fresh discovery URL.