Update submodules: plugins (new commits)

plugins:
    4cea1de Greg Holmes <greg@dmdirc.com>
            Make DummyController non final for testing

            Gerrit: http://gerrit.dmdirc.com/2593

Change-Id: Ia6694099700036a46fab1f25734b814fd832c5fc

modules/plugins

@@ -1 +1 @@
-Subproject commit ca45e4719f9d5d77a3ceabf740262ed941620608
+Subproject commit 4cea1de89eaa37e9369170364a3832ec2160af9e