docs: Mention step to setup nodes on OpenStack
The --setup step was missing which lead to cryptic error messages when
running the following step (calling the dummy test suite).
@@ -31,6 +31,10 @@ Setup
$ cd teuthology ; ./bootstrap install
$ source virtualenv/bin/activate
+* Setup the teuthology node::
+
+ $ teuthology-openstack --key-filename myself.pem --key-name myself --setup
+
Get OpenStack credentials and test it
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