main/p7zip: fix secinfo indentation

>>> ERROR: p7zip: secfixes comment must not have tabs:
#	  - CVE-2018-5996
>>> ERROR: p7zip: sanitycheck failed
7 jobs for !7357 with main/p7zip in 1 minute and 36 seconds
detached
Status Job ID Name Coverage
  Lint
passed #104906
x86_64 docker-alpine
lint

00:00:23

 
  Build
passed #104911
aarch64 ci-build docker-alpine
build-aarch64

00:00:54

passed #104912
armv7 ci-build docker-alpine
build-armv7

00:00:58

passed #104910
ppc64le ci-build docker-alpine
build-ppc64le

00:01:13

passed #104909
s390x ci-build docker-alpine
build-s390x

00:00:46

passed #104908
x86 ci-build docker-alpine
build-x86

00:00:39

passed #104907
x86_64 ci-build docker-alpine
build-x86_64

00:00:34