title: psycopg2 does not execute PostgreSQL function
body: <p>I'm trying to call a function from <code>psycopg2</code> like such:</p>
  
  <pre><code>conn = psycopg2.connect(host="name.host.ex", user="username", password="secret")
  cur = conn.cursor()
  cur.callproc("f_do_action", ["aaa", "bbb"])
  cur.close()
  conn.close()
  </code></pre>
  
  <p>When calling this function from <code>psql</code> everything works fine but using <code>psycopg2</code> nothing seems to happen. I get no exception. It just does not call out the function on the actual database.</p>
  
  <p>Also other queries from <code>psycopg2</code> work (<code>SELECT, INSERT</code>).</p>