Fixes Zend_Validate_StringLength::setEncoding() with ini_set

Closes #634

library/Zend/Validate/StringLength.php

@@ -205,7 +205,8 @@ class Zend_Validate_StringLength extends Zend_Validate_Abstract
             if (PHP_VERSION_ID < 50600) {
                 $result = iconv_set_encoding('internal_encoding', $encoding);
             } else {
-                $result = ini_set('default_charset', $encoding);
+                ini_set('default_charset', $encoding);
+                $result = ini_get('default_charset');
             }
             if (!$result) {
                 require_once 'Zend/Validate/Exception.php';

tests/Zend/Validate/StringLengthTest.php

@@ -179,6 +179,15 @@ class Zend_Validate_StringLengthTest extends PHPUnit_Framework_TestCase
     }
 
     /**
+     * @expectedException Zend_Validate_Exception
+     * @group GH-634
+     */
+    public function testWrongEncoding()
+    {
+        $this->_validator->setEncoding('');
+    }
+
+    /**
      * @ZF-4352
      */
     public function testNonStringValidation()