odp-execute: Refactor odp_execute_{actions, sample}()

odp-execute: Refactor odp_execute_{actions, sample}()

Firstly, with this change, the 'more_actions' parameter is removed and
is integrated into 'steal'. Then, every function that receives a batch
of packets with 'steal' set to true is responsible for freeing the
packets. Finally, odp_execute_actions() and odp_execute_actions__()
can be be merged.

This also fixes a memory leak in odp_execute_sample(), when the
subactions are not executed

Signed-off-by: Daniele Di Proietto <ddiproietto@vmware.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>