Bug 1846403

This is a backport request based on the following upstream issue:
https://github.com/containers/libpod/issues/6567

## Description

In podman 1.6.4 at least (used in RHEL-8.1 for OSP project), we're apparently unable to pass multiple --security-op parameters to podman run, for instance:

podman run --net host --name selinux-test --rm -ti --security-opt=label=level:s0 --security-opt=label=type:svirt_t --privileged centos:8 sh

Although the container is started, we don't see both options - only the latest is applied, at least according to podman inspect:

[...]
            "Annotations": {
                "io.container.manager": "libpod",
                "io.kubernetes.cri-o.ContainerType": "sandbox",
                "io.kubernetes.cri-o.Created": "2020-06-11T08:30:18.590733514Z",
                "io.kubernetes.cri-o.TTY": "true",
                "io.podman.annotations.autoremove": "TRUE",
                "io.podman.annotations.init": "FALSE",
                "io.podman.annotations.label": "type:svirt_t",
                "io.podman.annotations.privileged": "TRUE",
                "io.podman.annotations.publish-all": "FALSE",
                "org.opencontainers.image.stopSignal": "15"
            },
[...]
            "SecurityOpt": [
                "label=type:svirt_t"
            ],
[...]

## Steps to reproduce the issue:

    Run a container with multiple --security-opt as parameter

    Inspect the container

## Describe the results you received:

Apparently only the last param value is applied, all previous ones are just discarded

## Describe the results you expected:

We should see all the passed options in the SecurityOpt list

## Additional information you deem important
Apparently this isn't an issue anymore in podman-1.9.3 - maybe it's "just" a missing backport?

## Output of podman version:

podman version 1.6.4

## Output of podman info --debug:

debug:
  compiler: gc
  git commit: ""
  go version: go1.12.12
  podman version: 1.6.4
host:
  BuildahVersion: 1.12.0-dev
  CgroupVersion: v1
  Conmon:
    package: conmon-2.0.6-1.module+el8.1.1+5259+bcdd613a.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.0.6, commit: 6ffbb2ec70dbe5ba56e4bfde946fb04f19dd8bbf'
  Distribution:
    distribution: '"rhel"'
    version: "8.1"
  MemFree: 26823548928
  MemTotal: 29263876096
  OCIRuntime:
    name: runc
    package: runc-1.0.0-64.rc9.module+el8.1.1+5259+bcdd613a.x86_64
    path: /usr/bin/runc
    version: 'runc version spec: 1.0.1-dev'
  SwapFree: 4294963200
  SwapTotal: 4294963200
  arch: amd64
  cpus: 12
  eventlogger: journald
  hostname: overcloud-0-novacompute-0
  kernel: 4.18.0-147.8.1.el8_1.x86_64
  os: linux
  rootless: false
  uptime: 2h 6m 18.21s (Approximately 0.08 days)
registries:
  blocked: null
  insecure:
  - undercloud.ctlplane:8787
  search:
  - registry.access.redhat.com
  - registry.fedoraproject.org
  - registry.centos.org
  - docker.io
store:
  ConfigFile: /etc/containers/storage.conf
  ContainerStore:
    number: 15
  GraphDriverName: overlay
  GraphOptions: {}
  GraphRoot: /var/lib/containers/storage
  GraphStatus:
    Backing Filesystem: xfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  ImageStore:
    number: 8
  RunRoot: /var/run/containers/storage
  VolumePath: /var/lib/containers/storage/volumes

## Package info (e.g. output of rpm -q podman or apt list podman):

podman-1.6.4-4.module+el8.1.1+5885+44006e55.x86_64