BUG/MEDIUM: stick-tables: Don't let table_process_entry() handle refcnt

BUG/MEDIUM: stick-tables: Don't let table_process_entry() handle refcnt

Instead of having table_process_entry() decrement the session's ref
counter, do it outside, from the caller. Some were missed, such as when
an action was invalid, which would lead to the ref counter not being
decremented, and the session not being destroyable.
It makes more sense to do that from the caller, who just obtained the
ref counter, anyway.
This should be backporter up to 2.8.

(cherry picked from commit 71199e394c5e63fda7070cd7ae5b4b691411259d)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 1b2a06b994c0d537ca2da0af101c2b84735d67f9)
[cf: ctx adjt]
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit e9c299c31d67bebe68c22503a98b51da485cdca7)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>