Update submodules: plugins (new commits)

plugins:
    7756c48 Chris Smith <chris@dmdirc.com>
            Tidy up Apple a bit.

            Gerrit: http://gerrit.dmdirc.com/2956

Change-Id: If892163aaab6e86e4f61507a4501aeef27210063

modules/plugins

-Subproject commit c467a181790442dcf0b0c90e27a534723827b552
+Subproject commit 7756c48879eaac020aabff47998dc4dc087b80ea