Update submodules: plugins (new commits)

plugins:
    cbbc4e1 Chris Smith <chris@dmdirc.com>
            Collect plugin jars in dist folder, like before.

            Whenever we build a new jar -- or if the jar in dist is changed --
            copy it into the dist directory with a proper name.

            Gerrit: http://gerrit.dmdirc.com/4060

Change-Id: Id90e669ddf495249319e83438293c134203bc261