Pass method names to preprocessors by value.

lib/Predis/Commands/Preprocessors/ICommandPreprocessor.php

@@ -3,5 +3,5 @@
 namespace Predis\Commands\Preprocessors;
 
 interface ICommandPreprocessor {
-    public function process(&$method, &$arguments);
+    public function process($method, &$arguments);
 }

lib/Predis/Commands/Preprocessors/KeyPrefixPreprocessor.php

@@ -169,7 +169,7 @@ class KeyPrefixPreprocessor implements ICommandPreprocessor {
         return $this->_prefix;
     }
 
-    public function process(&$method, &$arguments) {
+    public function process($method, &$arguments) {
         if (isset($this->_strategies[$method])) {
             $this->_strategies[$method]($arguments, $this->_prefix);
         }

lib/Predis/Commands/Preprocessors/PreprocessorChain.php

@@ -22,7 +22,7 @@ class PreprocessorChain implements ICommandPreprocessorChain, \ArrayAccess {
         }
     }
 
-    public function process(&$method, &$arguments) {
+    public function process($method, &$arguments) {
         $count = count($this->_preprocessors);
         for ($i = 0; $i < $count; $i++) {
             $this->_preprocessors[$i]->process($method, $arguments);