title: sqldf not working after update
body: <p>When I run the first example from sqldf function documentation:</p>
  
  <pre><code>library(sqldf)
  a1s &lt;- sqldf("select * from warpbreaks limit 6")
  </code></pre>
  
  <p>I get an error:</p>
  
  <pre><code>Error in if (.allows_extensions(db)) { :missing value where TRUE/FALSE needed    
  </code></pre>
  
  <p>This error appeared today after updating some packages to their latest versions. Any suggestions how to fix this or how to revert to previous versions?</p>