sdk/elements/desktop/libfdk-aac.bst: update ref to head of correct branch
sdk/elements/desktop/libfdk-aac.bst: update ref to head of correct branch
The previous 4b07abf0 ref was the head of the "stripped" branch which does not include an encoder. The correct branch is "stripped2" (as per the track: header) which contains a stripped encoder, and the current head is ba7ffc9d.