Resolve "Cannot launch monteverdi if .ini config file is invalid"

Closes #1587 (closed)

Amazing how this bug fix is only about removing code ...

From Qt documentation:

void QSettings::sync()

This function is called automatically from QSettings's destructor and by the event loop at regular intervals, so you normally don't need to call it yourself.

They should add that not only you do not need to call it yourself, but you should also avoid using its status to throw system exceptions from the bottom of the stack, as errors are handled just fine by default Qt behavior, without writing one line of code.