Quitting awesome via the right-click-on-root menu stopped working

[psychon]

Commit d71bb66 added argument handling to awesome.quit. When run by awful.menu, the incorrect arguments that were previously just ignored now cause an error:

2016-10-29 13:54:48 W: awesome: luaA_dofunction:77: error while running function!
stack traceback:
    [C]: in function 'cmd'
    lib/awful/menu.lua:301: in function 'exec'
    lib/awful/menu.lua:441: in function 'press'
    lib/awful/button.lua:46: in function <lib/awful/button.lua:46>
    [C]: in function 'emit_signal'
    lib/wibox/widget/base.lua:367: in function <lib/wibox/widget/base.lua:334>
    (...tail calls...)
    lib/gears/object.lua:116: in function 'emit_signal'
    lib/wibox/drawable.lua:405: in function <lib/wibox/drawable.lua:400>
error: lib/awful/menu.lua:301: bad argument #1 to 'cmd' (number expected, got table)