ANDROID: xt_quota2: clear quota2_log message before sending

ANDROID: xt_quota2: clear quota2_log message before sending

Initialize message buffer for quota2_log to avoid sending
random data.

Mot-CRs-fixed: (CR)
CVE-Fixed: CVE-2021-0961

Bug: 196046570
Test: passed netd test suites
Fixes: 10cda83af99d ("ANDROID: netfilter: xt_quota2: adding the
original quota2 from xtables-addons")
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: Ic9f34aaa2593809b375fc649b74567190c99dc62
Signed-off-by: Gajjala Chakradhar <gajjalac@motorola.com>
Reviewed-on: https://gerrit.mot.com/2123623
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Tested-by: Jira Key
Reviewed-by: Xiangpo Zhao <zhaoxp3@motorola.com>
Submit-Approved: Jira Key
(cherry picked from commit 8e858f864cc16a7ccecb9522012a29655ed07653)