erp5_dms: Fixup PDF_getThumbnailList so that it works also with ERP5JS

Also, remove trailing whitespace

bt5/erp5_dms/SkinTemplateItem/portal_skins/erp5_dms/PDF_getThumbnailList.py

@@ -10,7 +10,7 @@ page_number = int(content_information.get('Pages', 0))
 limit = kw.get('limit', (0, 0))
 list_start = int(kw.get('list_start', 0))
 list_lines = int(kw.get('list_lines', 0))
-size = list_lines or limit[1]
+size = list_lines or int(limit[1])
 
 list_end = list_start + size
 page_list = range(page_number)