Merge pull request thephpleague#48 from ntomka/master

Fix non-string env vars handling in FtpAdapterDefinitionBuilder

Author: tgalopin

src/Adapter/Builder/FtpAdapterDefinitionBuilder.php

@@ -59,10 +59,10 @@ protected function configureOptions(OptionsResolver $resolver)
         $resolver->setAllowedTypes('timeout', 'scalar');
 
         $resolver->setDefault('ignore_passive_address', null);
-        $resolver->setAllowedTypes('ignore_passive_address', ['null', 'bool']);
+        $resolver->setAllowedTypes('ignore_passive_address', ['null', 'bool', 'scalar']);
 
         $resolver->setDefault('utf8', false);
-        $resolver->setAllowedTypes('utf8', 'bool');
+        $resolver->setAllowedTypes('utf8', 'scalar');
     }
 
     protected function configureDefinition(Definition $definition, array $options)