Update submodules: plugins (new commits)

plugins:
    32d11c6 Greg Holmes <greg@dmdirc.com>
            Remove annotations library.

            Gerrit: http://gerrit.dmdirc.com/3731

    d5ff594 Greg Holmes <greg@dmdirc.com>
            Tidy up DBus Media source a little bit.

            I have no tested this other than that it compiles.

            Gerrit: http://gerrit.dmdirc.com/3727

Change-Id: I670b244b93f5f58a5a419d7003f65aafc4a71ecc