Fix: simplify get next index in live

This fixes some case of unitialized status, use of bad ret value and
help modularize the get next index function.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: deadlock during rotation

The overwrite_lock is nested inside the viewer_stream_rotation_lock.
And the viewer_stream_rotate function is always called with the
viewer_stream_rotation_lock held.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: race with index file creation

Only the data thread should create the index file since it is
responsible of filling the FD field of the index struct in memory.
When the control thread is ready to write the index, the FD is already
set.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>