Update submodules: plugins (new commits)

plugins:
    76dd7cb Chris Smith <chris@dmdirc.com>
            Remove deprecated method call

            Gerrit: http://gerrit.dmdirc.com/3189

Change-Id: Ic739b93ee11de4bacb9eaf6d7e8446434a1c1886
Remove unused/deprecated methods.

Change-Id: I5ca2144c28c208aaaddce5c0eedff3b0ca52ff30
Reviewed-on: http://gerrit.dmdirc.com/3190
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager