fix a warning when session was destroyed and Session Handler is trying to write

gulliver/core/Session/PmSessionHandler.php

@@ -165,6 +165,10 @@ class PmSessionHandler //implements SessionHandlerInterface
      */
     public function write($id, $data)
     {
+        if (empty($this->db)) {
+            return null;
+        }
+
         $time = time();
         
         if(! isset($this->wstmt)) {

workflow/engine/src/Tests/ProcessMaker/Project/Adapter/BpmnWorkflowTest.php

@@ -21,7 +21,7 @@ class BpmnWorkflowTest extends \PHPUnit_Framework_TestCase
 
     public static function tearDownAfterClass()
     {
-        return false;
+        //return false;
         //cleaning DB
         foreach (self::$uids as $prjUid) {
             $bwap = Project\Adapter\BpmnWorkflow::load($prjUid);