[ffmpeg/f28] (10 commits) ...Add support for libaom

Summary of changes: 364f543... - Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass (*) 6a4ece2... Add spec fixes from rfbz #4964 (*) 0d05393... minors cuda fixes (*) a4a2002... Add without_opus switch (*) a00b8e1... Add without opus for rhel (*) a35810f... Disable nvenc for rhel (*) cac4887... Disable mfx for rhel (*) 4e0582e... Fixup without_mfx (*) 17ffa15... Update Changelog (*) d898f66... Add support for libaom (*) (*) This commit already existed in another branch; no separate mail sent