This fixes fate with FF_API_LAVF_BITEXACT disabled.
Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This allows having the samples accessible via different paths
on the target and on the host.
Signed-off-by: Martin Storsjö <martin@martin.st>

Signed-off-by: Mans Rullgard <mans@mansr.com>

This allows fate to run without errors with or without SAMPLES
being set.
Signed-off-by: Mans Rullgard <mans@mansr.com>

This makes only tests actually using avconv depend on it.
The remaining tests already depend on what they need.
Signed-off-by: Mans Rullgard <mans@mansr.com>