Update submodules: defaults (new commits)

defaults:
    4b1af57 Greg Holmes <greg@dmdirc.com>
            Add a mode alias

            Gerrit: http://gerrit.dmdirc.com/2794

Change-Id: I4c38923338eb267325cacc469acd33c1b02b4103

modules/defaults

@@ -1 +1 @@
-Subproject commit 4dfc47ca1a86d7fb44b9e974224b416946fec7f0
+Subproject commit 4b1af57f96eaaf0c2872b75c87ee0440f54a8d85