Set associative = true for cleanup job

Signed-off-by: Daniel Kesselberg <mail@danielkesselberg.de>

Author: kesselb

lib/private/Security/VerificationToken/CleanUpJob.php

@@ -59,7 +59,7 @@ public function __construct(ITimeFactory $time, IConfig $config, IVerificationTo
 
 	public function setArgument($argument) {
 		parent::setArgument($argument);
-		$args = \json_decode($argument);
+		$args = \json_decode($argument, true);
 		$this->userId = (string)$args['userId'];
 		$this->subject = (string)$args['subject'];
 		$this->pwdPrefix = (string)$args['pp'];