netfilter: xt_qtaguid: fix crash after using delete ctrl command

* Crash fix
The delete command would delete a socket tag entry without removing it
from the proc_qtu_data { ..., sock_tag_list, }.
This in turn would cause an exiting process to crash while cleaning up
its matching proc_qtu_data.

* Added more aggressive tracking/cleanup of proc_qtu_data
This should allow one process to cleanup qtu_tag_data{} left around from
processes that didn't use resource tracking via /dev/xt_qtaguid.

* Debug printing tweaks
Better code inclusion/exclusion handling,
and extra debug out of full state.

Change-Id: I735965af2962ffcd7f3021cdc0068b3ab21245c2
Signed-off-by: JP Abgrall <jpa@google.com>