fix(HLS): Fix interpretation of DEFAULT and AUTOSELECT
fix(HLS): Fix interpretation of DEFAULT and AUTOSELECT

Previously, we treated the mere presense of either the DEFAULT or
AUTOSELECT attributes as an indication of a primary language.
However, AUTOSELECT should not be used in this way at all, and both
attributes can have a value of NO, so mere presence or absence is not
enough.

Instead, we must check for DEFAULT=YES to indicate a primary language.

Fixes #2880

Change-Id: Ie107f079c06beb89ee5a6a51375af7a72fdd9021

shaka-project/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,tvoli/shaka-player,tvoli/shaka-player