[phb]: Fix poudriere ports tree creation instructions

[fernape]

Summary

• If using CURRENT, we need to use Git
• We need the -B flag because our "master" branch is called "main".

Test Plan

• With current instructions:

[00:00:00] Cloning the ports tree...warning: Could not find remote branch master
to clone.
fatal: Remote branch master not found in upstream origin
[00:00:00] Error:  fail
[00:00:00] Error while creating ports tree, cleaning up.

• Apply patch and make documentation
• Review result in browser

[gbe]

LGTM for the documentation change, but I am not so deep into poudriere stuff.

[fernape]

In D29724#668396, @gbe wrote:

LGTM for the documentation change, but I am not so deep into poudriere stuff.

Hi Gordon,

Thanks for the review. I'm pretty positive of the change, but if you feel more comfortable I can bring another pair of eyes from a ports committer to validate the change, or we can ask @0mp since he is a ports committer too.

[gbe]

In D29724#668399, @fernape wrote:

In D29724#668396, @gbe wrote:

LGTM for the documentation change, but I am not so deep into poudriere stuff.

Hi Gordon,

Thanks for the review. I'm pretty positive of the change, but if you feel more comfortable I can bring another pair of eyes from a ports committer to validate the change, or we can ask @0mp since he is a ports committer too.

@0mp is already in the reviewers list. If you know someone that could have look at the poudriere syntax, just add him as a reviewer.

[0mp]

Sounds good to me!