Update submodules: plugins (new commits)

plugins:
    0e4e578 Chris Smith <chris@dmdirc.com>
            Remove all IdentityManager references from plugins

            Everything now references an IdentityController or IdentityFactory,
            and obtains them by injection (or local plugin state) rather than
            using a singleton method.

            Gerrit: http://gerrit.dmdirc.com/2751

Change-Id: I31ba535033101c67d0e6d3dc3d8a0b30252eddc2

modules/plugins

@@ -1 +1 @@
-Subproject commit 532274fe1a577294814ec97ba7f1aafcfe3a48df
+Subproject commit 0e4e578f757c2b55b01ffb99a81a17b465b1c586