Update submodules: plugins

plugins:
    99aa9dc Greg Holmes <greg@dmdirc.com>
            Fix window flashing never stopping.

            Gerrit: http://gerrit.dmdirc.com/2318

Change-Id: I3454bafa6ce500337a35363dfaa8a11c1ad96802

modules/plugins

@@ -1 +1 @@
-Subproject commit c48b8b89ca601e446c4ed80d87d7463058e48ee2
+Subproject commit 99aa9dcdebc434fe8534fec7d284723c896b62af