Fix crash on reload
Fix crash on reload

If sway is reloaded using a bindsym which has multiple commands, it
failed to detect the reload command, didn't create a duplicate of the
binding and would crash because the reload command frees the bindings.

For example:

    mode system {
        bindsym r reload, mode default
    }

In this example, the binding->command is "reload, mode default".

Fixes #2545

ascent12/sway,ascent12/sway,taiyu-len/sway,1ace/sway,taiyu-len/sway,1ace/sway,SirCmpwn/sway,1ace/sway,taiyu-len/sway,ascent12/sway