Check if dir exists before glob()

I get an Invalid argument supplied for foreach() exception otherwise (on 1 system, other system works fine) (on develop this time)

src/Rocketeer/RocketeerServiceProvider.php

@@ -359,7 +359,7 @@ protected function loadFileOrFolder(Container $app, $handle)
  }
 
  // Else include its contents
- else {
+ elseif (is_dir($file)) {
  $folder = glob($file.'/*.php');
  foreach ($folder as $file) {
  include $file;