An alias is valid is none is selected.

Change-Id: Id853197d3884ad18d8c90e53e930f9680170e994
Fixes-Issue: CLIENT-518
Reviewed-on: http://gerrit.dmdirc.com/3629
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Shane Mc Cormack <shane@dmdirc.com>
Update submodules: plugins (new commits)

plugins:
    24fa126 Greg Holmes <greg@dmdirc.com>
            Fix broken list selection model implementation.

            Fixes-Issue: CLIENT-515
            Gerrit: http://gerrit.dmdirc.com/3630

    4b5728f Greg Holmes <greg@dmdirc.com>
            Reset scrollpane when setting response text.

            Fixes-Issue: CLIENT-516
            Gerrit: http://gerrit.dmdirc.com/3628

Change-Id: I6b24ee74092e6a7e5ab1ce25868464682c9cecd2