[mgmt-framework] Fix docker image build failure for docker-sonic-mgmt-framework-dbg.

[liushilongbuaa]

Why I did it

docker-sonic-mgmt-framework-dbg.gz need to install openssh-client.
Setting up openssh-client need to run command ‘groupadd’
But docker docker-sonic-mgmt-framework '/etc/group' is a fake file.
Related: #6148

How I did it

How to verify it

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)

[liushilongbuaa]

validation job: https://dev.azure.com/mssonic/build/_build/results?buildId=54323&view=results

[liushilongbuaa]

2021-11-25T18:39:46.0862872Z + sudo LANG=C DOCKER_HOST= chroot ./fsroot-broadcom sonic-package-manager install --from-tarball target/docker-dhcp-relay-dbg.gz -y -v DEBUG
2021-11-25T18:39:46.0863745Z debug: inspecting image labels docker-gbsyncd-credo-dbg:latest
2021-11-25T18:39:46.0867781Z debug: image docker-gbsyncd-credo-dbg:latest labels successfully: {'Tag': 'master.54366-879c18417', 'com.azure.sonic.manifest': '\n{\n "version": "1.0.0",\n "package": {\n "version": "1.0.0+dbg",\n "depends": [],\n "name": "gbsyncd"\n },\n "service": {\n "name": "gbsyncd",\n "requires": [],\n "after": [],\n "before": [],\n "dependent-of": [],\n "asic-service": false,\n "host-service": true,\n "warm-shutdown": {\n "after": [],\n "before": []\n },\n "fast-shutdown": {\n "after": [],\n "before": []\n }\n },\n "container": {\n "privileged": false,\n "volumes": [],\n "tmpfs": []\n },\n "cli": {\n "config": "",\n "show": "",\n "clear": ""\n }\n}', 'com.azure.sonic.versions.libsairedis': '1.0.0', 'com.azure.sonic.versions.libswsscommon': '1.0.0'}
2021-11-25T18:39:46.0870048Z debug: checking dependencies for
2021-11-25T18:39:46.0870375Z debug: checking conflicts for
2021-11-25T18:39:46.0870894Z debug: checking dependencies for dhcp-relay
2021-11-25T18:39:46.0871723Z Failed to install target/docker-dhcp-relay-dbg.gz: Package dhcp-relay requires database^1.0.0 but it is not installed