Update submodules: plugins (new commits)

plugins:
    804a88e Greg Holmes <greg@dmdirc.com>
            Validate swing inputfield on key release.

            Fixes-Issue: CLIENT-385
            Gerrit: http://gerrit.dmdirc.com/2614

    017e900 Greg Holmes <greg@dmdirc.com>
            Fix broken addon browser.

            Download to a valid location.  Stop silently failing, show errors to used.

            Fixes-Issue: CLIENT-393
            Gerrit: http://gerrit.dmdirc.com/2615

Change-Id: Iddadc2b0390db8226de62f172bea5c1359b7d8e5