Update submodules: plugins (new commits)

plugins:
    e03723f Chris Smith <chris@dmdirc.com>
            Tidying.

            Gerrit: http://gerrit.dmdirc.com/3923

    8e8e065 Chris Smith <chris@dmdirc.com>
            Random minor tidying

            Gerrit: http://gerrit.dmdirc.com/3919

Change-Id: I0abbaddd10a07451e05683cece6bb6635b946cf6