CrossRoads:
Leave it connected unless you plan to implement hardware flow control, in which case you'll need a bunch of other connections as well.
I think the point was that he wants to connect the (hardware) serial interface to the MIDI board, not the CP2102 USB interface, and was wondering whether this pin needed to be connected to anything.
The answer is no - no need to to connect it to anything, just let it hang loose. 