using tmp folder within the xtreemfs volume instead of /tmp

xtreemfs_client/OSDManager.py

@@ -442,10 +442,13 @@ class OSDManager(object):
     moves a folder from one OSD to another OSD. you may specify a temporary folder.
     '''
 
-    def move_folder_to_osd(self, folder_id: str, new_osd_id: str, tmp_dir='/tmp/move_folder_tmp_dir'):
+    def move_folder_to_osd(self, folder_id: str, new_osd_id: str, tmp_dir=None):
         folder_path = os.path.join(self.get_target_dir(folder_id),
                                    os.path.split(folder_id)[1])
 
+        if tmp_dir is None:
+            tmp_dir = os.path.join(self.pathToMountPoint, self.volumeName, '.tmp_move_folder')
+
         start_time = 0
         if self.debug:
             start_time = time.time()