multimedia/svt-av1: unbreak after r493624

> Fetching all distfiles required by svt-av1-s20180222 for building

> SHA256 Checksum OK for OpenVisualCloud-SVT-AV1-s20180222-425ba77_GH0.tar.gz.

> SHA256 Checksum OK for 89.diff.

> SHA256 Checksum mismatch for 103.diff.

> Giving up on fetching files: 103.diff

Make sure the Makefile and distinfo file (/usr/ports/multimedia/svt-av1/distinfo)
are up to date. If you are absolutely sure you want to override this
check, type "make NO_CHECKSUM=yes [other args]".

• Error code 1

Changes: https://github.com/OpenVisualCloud/SVT-AV1/compare/425ba77...df11eb0
Reported by: pkg-fallout