Update submodules: plugins (new commits)

plugins:
    70de711 Chris Smith <chris@dmdirc.com>
            Remove all UpdateChecker.getManager() calls.

            Down with static methods! Temporarily up with deprecated methods on horrible
            global state objects!

            Gerrit: http://gerrit.dmdirc.com/3027

Change-Id: I5c3549e1a12a7419237936a15c6fc9104eef3e9e