The fate test is changed because the reference file depends on the use of
non cleared data at the very
end. Alternatively we could upload a new reference file, though that would
then have to be changed every time the handling of a truncated frame changes
or theres a change to error concealment, each time adding a new file ...

Fixes use of uninitialized memory
Fixed: msan_uninit-mem_7f3c02b81363_2787_RLG2_19.rm
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>