We're seeing failures due to system load. In theory we've set process
nice levels which should compensate for this. Add debugging so we can
find out if they're being correctly applied.
(From OE-Core rev: 1e4e345bba8216b9b5623682206a7dae7cad261c)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>