[hotfix] delete and sync the child table customization (#4371)

* [hotfix] delete and sync the child table customization

* Update utils.py

frappe/modules/utils.py

@@ -100,8 +100,9 @@ def sync_customizations_for_doctype(data):
 	update_schema = False
 
 	def sync(key, custom_doctype, doctype_fieldname):
-		frappe.db.sql('delete from `tab{0}` where `{1}`=%s'.format(custom_doctype, doctype_fieldname),
-			doctype)
+		doctypes = list(set(map(lambda row: row.get(doctype_fieldname), data[key])))
+		frappe.db.sql('delete from `tab{0}` where `{1}` in ({2})'.format(
+			custom_doctype, doctype_fieldname, ",".join(["'%s'" % dt for dt in doctypes])))
 
 		for d in data[key]:
 			d['doctype'] = custom_doctype