mms: Remove non-utf8 characters

Certain softwares get badly confused.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  mms: Remove non-utf8 characters

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avfilter/avectorscope: fix {} mistake in alloc check.
avcodec/wnv1: clear padding area of rbuf

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7faa48586020_2145_MAILTEST.AVI
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>