Revert "QMediaNetworkPlaylistProvider: Upon error parsing, stop parsing."

This reverts commit 0ed18d84

.
The same patch was submitted in both 5.3 and 5.4 branches. It should
have been pushed only to 5.3.

Change-Id: I9e2974886190dfb2e5def5bc325c58f6e7783f55
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>