Nintendo just said that the 3DS reboot of Ocarina of Time will ship on June 19 in the US. It's also coming out June 17 in Europe.
Looks like the Spanish distributor who outed the date in late March was correct.
Shigeru Miyamoto has said that players will experience new things “one after another,” in the remake of Ocarina of Time for 3DS, but that it still “definitely a Zelda game," and is "crammed with interesting things” not in the original.
The Master Quest is one of these "interesting" things.