Update submodules: plugins (new commits)

plugins:
    b4c92b5 Greg Holmes <greg@dmdirc.com>
            Move Profile to core

            Fixes-Issue: CLIENT-464
            Depends-On: Idf8b7726de5132bf67836b7613ba7fd616f3d414
            Gerrit: http://gerrit.dmdirc.com/3304

    e10a3cb Greg Holmes <greg@dmdirc.com>
            Pack restart dialog on display.

            Fixes-Issue: CLIENT-478
            Gerrit: http://gerrit.dmdirc.com/3302

    29fd519 Greg Holmes <greg@dmdirc.com>
            Remove unused method.

            Gerrit: http://gerrit.dmdirc.com/3301

Change-Id: I477b430d79c406b2fda65599541de441d2d04cd7