Tidy up some TabCompleter usages.

Change-Id: I1d61d1895025f3b7febd7cae1e8411d0b198f141
Depends-On: I2eb5ac89568b524ef13cf1d455eb5b51904c806c
Reviewed-on: http://gerrit.dmdirc.com/2867
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Update submodules: plugins (new commits)

plugins:
    101cd81 Chris Smith <chris@dmdirc.com>
            Tidy up some TabCompleter usages.

            Depends-On: I1d61d1895025f3b7febd7cae1e8411d0b198f141
            Gerrit: http://gerrit.dmdirc.com/2866

Change-Id: Ieaf99b32c5bcd51ec4274a4d091b31c8393236a4