Filip Roséen authored Apr 04, 2017 and Thomas Guillem committed Apr 05, 2017

A negative value now denotes that the default timeout associated with
the background worker shall be used, 0 means that there shall be no
timeout.

This fixes a regression where the documented behavior of
playlist_preparser_Push differed from the underlying implementation.

Signed-off-by: Thomas Guillem <thomas@gllm.fr>