Update submodules: plugins (new commits)

plugins:
    f59ebab Greg Holmes <greg@dmdirc.com>
            Fix dialog key listener.

            Fixes-Issue: CLIENT-407
            Gerrit: http://gerrit.dmdirc.com/2805

    6b4d333 Greg Holmes <greg@dmdirc.com>
            Tidy up NSD

            Gerrit: http://gerrit.dmdirc.com/2804

Change-Id: Ic9001a44cdf2dd8396b760b99dc72c892d1fa877