doc/APIchanges: fill in missing hashes and dates
doc/APIchanges: mark the place where 9 was branched
pcmdec: replace a reachable assert with an error check

Libavformat should not make any assumptions about values returned from
other libraries. This assert is easily reachable by using a non-raw
codec id.
FATE: force FLAC in the lavf ogg test

Since b0c2c09, vorbis would be used if libvorbis is compiled in.
hevc: update conformance streams

New streams: LTRPSPS_A_Qualcomm_1, SLPPLP_A_VIDYO_1, VPSID_A_VIDYO_1
Updated streams: EXT_A_ericsson_4, NUT_A_ericsson_5, RPS_C_ericsson_5,
  RPS_D_ericsson_6

Signed-off-by: Anton Khirnov <anton@khirnov.net>