Remove useless statements.

Filter/ModelFilter.php

@@ -86,10 +86,6 @@ class ModelFilter extends Filter
             throw new \RunTimeException('Invalid mapping type');
         }
 
-        if (!$this->getOption('field_name')) {
-            throw new \RunTimeException('Please provide a field_name options');
-        }
-
         $newAlias = $alias.'_'.$field;
 
         $queryBuilder->leftJoin(sprintf('%s.%s', $alias, $field), $newAlias);

Guesser/FilterTypeGuesser.php

@@ -52,7 +52,6 @@ class FilterTypeGuesser implements TypeGuesserInterface
         $options['parent_association_mappings'] = $parentAssociationMappings;
 
         if ($metadata->hasAssociation($propertyName)) {
-            $multiple = $metadata->isCollectionValuedAssociation($propertyName);
             $mapping = $metadata->getAssociationMapping($propertyName);
 
             switch ($mapping['type']) {

Guesser/TypeGuesser.php

@@ -44,7 +44,6 @@ class TypeGuesser implements TypeGuesserInterface
         list($metadata, $name) = $ret;
 
         if ($metadata->hasAssociation($property)) {
-            $multiple = $metadata->isCollectionValuedAssociation($property);
             $mapping = $metadata->getAssociationMapping($property);
 
             switch ($mapping['type']) {