HLS: handle EXT-X-DISCONTINUITY-SEQUENCE correctly

Because EXT-X-DISCONTINUITY is a prefix of EXT-X-DISCONTINUITY-SEQUENCE,
putting EXT-X-DISCONTINUITY first in an if-startsWith/else-if-startsWith
block would cause EXT-X-DISCONTINUITY-SEQUENCE be parsed as
EXT-X-DISCONTINUITY.

Bug: 28320768
Change-Id: I667b97b0e2050324eec26779e6a2dae7900e96b8
1 file changed