Remove special case svn to git translations for FFmpeg.

This reverts the relevant pieces of https://codereview.chromium.org/9359045/

I'll update Chrome's DEPS file to use the new syntax and roll
deps2git at the same time in a followup CL.

BUG=329002
TEST=deps2git outputs correct DEPS.

Review URL: https://codereview.chromium.org/190853003

git-svn-id: http://src.chromium.org/svn/trunk/tools/deps2git@270695 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
3 files changed