You 're alright but I made test travis early with latin1 and it had problem in encoding:
<pre>
191 $ pgvm cluster create latin1_cluster --encoding=latin1 --locale=en_US.ISO-8859-1
192 bash: warning: setlocale: LC_ALL: cannot change locale (en_US.ISO-8859-1)
</pre>

https://travis-ci.org/fike/pgvm/builds/4183755