Bug#1091859: rosegarden: crashes after closing the "Mange MIDI Devices" window

[Ted Felix <ted@tedfelix.com>]

  Thanks for the backtrace.  It appears as if we are using an 
invalidated iterator in this case.  It's the kind of thing that will 
cause serious problems randomly and without warning.  I will have a 
closer look and consider releasing a 24.12.1.