I don't think the Taboo was disabled. My case for the Taboo spell still being active is the following.
- The Taboo spell is used to identify the location someone said a specific word
- The Taboo spell did not necessarily identify who the speaker was. Nothing specifically mentioned this. The arriving Death Eaters didn't say anything indicating they knew who the person was before arrival.
- The use of the word almost certainly was directed to notify the Death Eaters instead of Voldemort himself. It seems unlikely that he would personally track down every person speaking his name. He never showed up, and it seems unlikely people would show up so quickly if Voldemort had to direct people to go search an area.
- While Ron mentioned that the Taboo could break through some protections, it was not able to break through the Fidelius charm on 12 Grimmauld Place.
- You cannot Apparate into Hogwarts. The Death Eaters did not Apparate into the castle after the name was used. So the Taboo spell was not stronger than Hogwart's protections.
- Hogwarts had at least 3 Death Eaters on staff (Snape and both Carrows), and probably more close by.
- If a student spoke the name 'Voldemort' at Hogwarts, you would expect the Death Eaters in residence to handle the problem, since the Taboo was apparently not strong enough to break the anti-Apparition spells.
So when Harry, and/or other people used the name when he arrived at Hogwarts it certainly could/would have notified the people responsible for monitoring the spell. But after he arrived on scene he was pretty quickly joined by a lot of backup.
Once the battle began it really wouldn't have made a lot of difference if he said the name. All the death eaters were there, or on the way to join the battle. Speaking the name again certainly wouldn't make people try to show up any faster.
At best saying the name might reveal the specific location of Harry at that specific point in time he said the name, but since everyone was prevented from Apparating, that wouldn't really help the Death Eaters much, since they would have had to fight their way to that location.
Given the facts, and conjectures, the Taboo spell would not have needed to be disabled to explain a lack of immediate response in conjunction with any uses of Voldemort's name after Harry returned to Hogwarts.