Fix exception when using non-device parameters in DeviceCommands
Fix exception when using non-device parameters in DeviceCommands

This happens e.g. when starting udiskie with:

    udiskie -ANT --notify-command "echo {event}"

Regression introduced by:

    Commit:  ab7097c0ee8b789486f3a79b0ecd3759cf494f88
    Subject: Remove deprecated syntax for positional parameter in format strings

coldfix/udiskie,coldfix/udiskie