Update submodules: plugins (new commits)

plugins:
    528583b Chris Smith <chris@dmdirc.com>
            Push some SwingController dependencies out a bit.

            Gerrit: http://gerrit.dmdirc.com/3053

Change-Id: I683cd68cd3f42ca3c2dacf2a959fc606116dbd33
Update submodules: plugins (new commits)

plugins:
    272fb2b Chris Smith <chris@dmdirc.com>
            Remove some more usages of SwingController.

            Gerrit: http://gerrit.dmdirc.com/3054

Change-Id: I4fdd3b0cdc13ff51dda31f1d651171f9948dafea