ofp-util: Fix null pointer dereference in ofputil_pull_buckets().

Found by clang-analyzer.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
ofp-msgs: Correct code for queue configuration messages in OpenFlow 1.0.

Reported-by: Simon Jouet <simon.jouet@gmail.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>