Hello,
You are refering to the coolant vent line, most are probably blocked solid anyway after a few years use, with the real risk of being branded a heretic, I think you can get away with blocking it off completely, but it will take a few days for all the air to bleed out of the cooling system(don't ask me how I know :p
).
The banjo bolts should be in stock at the dealer parts counter.
Hope that helps.