Update submodules: plugins (new commits)

plugins:
    77963ce Greg Holmes <greg@dmdirc.com>
            Move AliasDialogModelHandler and remove useless controller.

            Depends-On: Ic547ed6e12879c7c6ea77d2c6766989c01dff640
            Gerrit: http://gerrit.dmdirc.com/3579

Change-Id: I1fd82b4e3d958de3cb60d0d762b6302631ee6867