It has no effect whatsoever since the major bump.
Replace the flag's documentation to reflect this as well.
Signed-off-by: James Almer <jamrial@gmail.com>
Preparation for potentially disabling merged side data by default in the
libs. Do this in particular because it affects fate tests.
The changed tests either reflect added packet side data, or the changed
packet size due to merged side data removal reducing the packet size.
