[iccpd] Fix iccpd env

[globaltrouble]

Why I did it

mclagsyncd source is in sonic-swss repo, its binary is inside iccpd container and binary use platform env var https://github.com/Azure/sonic-swss/blob/ef6b5d48297f7f19a8ec57e2d7b997fd0919bb9d/mclagsyncd/mclaglink.cpp#L191

But platform env is set only inside swss container services, for example https://github.com/Azure/sonic-buildimage/blob/7d40384c58848c368ecf7b2c520f7a17fcbc8bdb/dockers/docker-orchagent/orchagent.sh#L7

So code doesn't support branch with port isolation group, because env is not set.

How I did it

Added env to iccpds start script, like in orchagent

How to verify it

• build sonic with iccpd
• configure mclag
• wait iccpd bring up
• /var/log/syslog must contains row with text Delete all isolation group destination ports, hence code branch with port isolation group was used instead of ACL

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)

[globaltrouble]

@gitsabari note, previously code branch with port isolation group was dead and port isolation group was not used.

[globaltrouble]

@lguohan could you please review it?

[globaltrouble]

@qiluo-msft could you please review it?

[globaltrouble]

@lguohan could you please review it?

[globaltrouble]

@qiluo-msft could you please review it?

[globaltrouble]

@gechiang could you please review it?

[akokhan]

@gitsabari, @Praveen-Brcm , please take a look

[globaltrouble]

@lguohan could you please help to review it?

[gechiang]

Looks good to me. But let's wait for @gitsabari, @Praveen-Brcm to review and approve.

[Praveen-Brcm]

Changes looks good to me. Please add me to the reviwers list to approve. Thanks.

[gechiang]

Changes looks good to me. Please add me to the reviwers list to approve. Thanks.

@Praveen-Brcm
Looks like I am not able to add you as a reviewer... but since you have already reviewed it and approved, I will go ahead approve it and merge it.
Thanks!

[gitsabari]

changes looks good to me also. Please add me to reviewer list to approve

[gechiang]

LGTM! @Praveen-Brcm has also reviewed and approved.