Fix init.sh to work with a tag

[johnbelamaric]

What type of PR is this?
/kind bug

What this PR does / why we need it
init.sh currently only works if the value passed into nephio-test-infra-branch is a branch, not if it is a tag. This is a problem for creating instructions that enable building a sandbox from a single command, based on a tag (e.g., v1.0.0).

Which issue(s) this PR fixes:
Partially fixes nephio-project/nephio#328

This will fix it for v1.0.1 and later. For v1.0.0, we need to create a branch to use, and tweak the instructions to use that branch name. Either that, or we need to move the v1.0.0 tag to a commit after this PR merges.

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[nephio-prow]

@johnbelamaric: The label(s) kind/bug cannot be applied, because the repository doesn't have them.

In response to this:

What type of PR is this?
/kind bug

What this PR does / why we need it
init.sh currently only works if the value passed into nephio-test-infra-branch is a branch, not if it is a tag. This is a problem for creating instructions that enable building a sandbox from a single command, based on a tag (e.g., v1.0.0).

Which issue(s) this PR fixes:
Partially fixes nephio-project/nephio#328

This will fix it for v1.0.1 and later. For v1.0.0, we need to create a branch to use, and tweak the instructions to use that branch name. Either that, or we need to move the v1.0.0 tag to a commit after this PR merges.

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[johnbelamaric]

/hold

Let me try this first. I have tested the individual bits but not the final result yet.

[johnbelamaric]

/hold cancel

OK, it's working now.

[vjayaramrh]

reviewed, but not tested.
/lgtm

[electrocucaracha]

/lgtm

[nephio-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: electrocucaracha, johnbelamaric, vjayaramrh

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