awx: add check is_array

public_html/deployment/plugins/rollout/awx/rollout_awx.php

@@ -178,7 +178,7 @@ class rollout_awx extends rollout_base {
         $sCmdChecks='';
         if($aConfig['extravars']){
             $aTmp=json_decode($aConfig['extravars']);
-            if (!$aTmp || !count($aTmp) ){
+            if (!$aTmp || !is_array($aTmp) || !count($aTmp) ){
                 $sCmdChecks.='echo "ERROR: Value in extravars has wrong Syntax - this is no JSON: '.$aConfig['extravars'].'"; exit 1; ';                
             }
             $aConfig['extravars']=json_encode($aTmp);