This sort of reverts 096da450. The deadlock
mentioned there is not spelled out in detail, but likely results from the
streaming thread trying to acquire the filter lock while a main thread which
is holding the filter lock waits for the streaming thread to finish. However,
DirectShow documentation (and manual testing) suggests that the correct way
to avoid this problem is simply to never take the filter lock from the
streaming thread. Since we currently don't do this anymore, it should be safe
to reinstate this lock.
Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>